Patent Description:
Security is a core need for digitization, in particular because due to Industry <NUM>, Internet of Things (IoT) and new access technologies, such as <NUM>, the attack surface of entities is to become larger. For example, there have been <NUM> billion IoT connected devices in <NUM> while <NUM> billion devices are forecast by <NUM>. Meanwhile, the number of successful large-scale cyber-attacks is rising (e.g. Emotet and WannaCry). In addition, the asymmetry in the cyberwarfare is increasing. The ability to harm enterprises, organizations and even states is increasing, despite those entities invest more in their defense infrastructure.

In this context one fundamental question for the adopters of digitization and new access technologies is, how they could be well equipped against security threats. Especially, the following three points pose an immense challenge, with which existing security measures and tools have not been able to cope:.

Due to these developments and the limitation of existing solutions, malicious users with low level of expertise have become capable to hack large organizations.

<CIT> shows a device and method for acquiring second-level domain name information associated with a main domain name. The device comprises: a webpage crawling module which is configured to crawl a webpage content of which the URL is set as a main domain name; and a first domain name acquisition module which is configured to analyze the crawled webpage content, so as to acquire second-level domain name information associated with the main domain name in the webpage content.

To address the issues raised above, it is important to discover and evaluate the attack surface of an entity (company, organization, etc.) in real time. First, a comprehensive inventory of the IT infrastructure of the entity is automatically retrieved. Second, an enhanced in time vulnerability analysis and evaluation of the discovered IT infrastructure is performed. The information gathered is relevant for any company to accelerate management discussions and to take appropriate IT security decisions.

This patent application deals with the first point - namely, the automatic and dynamic asset discovery. This enables an entity to have always an overview of their online assets, respectively IT systems (IP addresses, domains and subdomains) from an external point of view, in particular the view of malicious hackers.

One important aspect of the automatic and dynamic discovery of IT systems is the automatic and dynamic determination and identification of main domains that belong to an entity.

The objective of the undelaying invention is to provide a method for automatic and dynamic determination and identification of main domains belonging to an entity which provides a comprehensive and up-to-date overview of the active/online domain names of an entity in an efficient way, in particular wherein the determined and identified main domain overview could be used for evaluation of the attack surface of the entity. Furthermore, it is an objective of this invention to provide a computer system, which is suitable to perform the method. Moreover, it is objective invention to provide a program product for automatic and dynamic determination and identification of main domains, when executed by the computer system, causes computer system to perform the method steps.

The underlying objective is solved by a method which has the features of the first claim. Advantageous embodiments of the invention are given by the dependent claims.

The method according to the invention comprises the following steps performed by a computer system:.

By performing the searching step a search list is generated on basis of the initial target name, wherein the initial target name could be the name or title of the entity or organization, e.g. "T-System" or "T-Mobile US", and may be defined by a user via an input device of the computer system or automatically by the computer system. The search list preferably comprises at least one list of uniform resource locators (URLs) or at least one list of domains. The at least one list of uniform resource locators is a collected from the at least one first data source by using the target name as input or query for the at least one first data source. For example, the ULRs provided by the first data source are "https://www. com/de/en", "https://www. com/de/en/data-privacy" or the like. Particularly preferably the list of domains is extracted from the list of uniform resource locators (URLs). For example, domains are "www. com" or the like. The list obtained from the at least one first data source in this way forms the basis for determining the main domains associated with the target name.

For the determination of the search list, the computer system uses the input or the query to get access to the at least one first data source, for example a merge and acquisition database, like S&P Capital IQ, Amadeus or an official database/register (e.g. in Germany the Bundesanzeiger with the homepage "https://www. bundesanzeiger. de/"), or a search engine, like Google, Yahoo, Bing or Duckduckgo. By doing so the computer system efficiently generates a broad up-to-date overview of relevant URLs and/or domains related to the target name. On basis of the search list by performing the extraction step the computer system extracts the list of main domains, in particular second-level domains, like "t-systems. By doing so the computer system determines an up-to-date overview of relevant main domains.

For each main domain of the list of main domains the number of appearances within the list of main domains is determined in the counting step. The number of appearances represents the first score of the corresponding main domain. The first score of each main domain is a measure for the identification of this main domain. The more frequently the main domain appears in the extracted list of main domains, the more likely it is that this main domain is related to the target name, respectively the entity or organization.

In addition, to identify the main domains related with the target name a validation keyword is generated on basis of the target name within the keyword generation step and a validation keyword factor is assigned to the validation keyword. The validation keyword is used within the subsequent scoring step in order to determine the second score, whereas the second score of each main domain corresponds to the multiplication of the number of appearances of the validation keyword within a second data source with the corresponding validation keyword factor. By querying the second data source and determining the second score a more reliable identification of the main domains could be performed by the computer system.

Finally, the first score and the second score of each main domain of the list of main domains are added to determine the final score of the main domain. By doing so a two-step method for the identification of a main domain to a target name is realized by the computer system, that provides an automatic and reliable identification of the main domains by the computer system.

According to an aspect of the invention the method comprises an enrichment step, wherein enriched target names are generated by appending identification words to the target name, and wherein the enriched target names are used as input to at least one first data source within the searching step. Identification words are for example "imprint", "privacy", "data protection", "website" or the like. By the appending of identification words provides preferably a more focused search for relevant URLs and domains within the at least one first data source. Advantageously, the search can be directed to URLs or domains that contain information that are related to the identification of the main domain.

According to an aspect of the invention the searching step comprises the usage of the target name and/or the enriched target name as input for more than one first data source, wherein a list of uniform resource locators or a list of domains is generated for each fist data source, and wherein the search list is generated by aggregation of the lists of uniform resource locators or the lists of domains of the first data sources. The search lists collected from each first data source are aggregated to a single search list, wherein the repetitions of URLs a and domain are avoided. The usage of more than one first data sources provide the broader database for the determination of main domains that are related to the target name and or the enriched target name.

According to an aspect of the invention the extraction step contains an additional filter step, in which main domains that are comprised in a blacklist are filtered out of the list of main domains. The additional filter step provides the opportunity to filter out domains that are not related to the target name, respectively the entity. Domains that should not be further considered by this method are stored within the blacklist. Preferably the blacklist contains general information domains, like encyclopedias or government registers. For example, domains within the blacklist are "Wikipedia", "Bloomberg" or the like. The entries of the blacklist could be generated manually or automatically. Preferably the entries of the blacklist are generated automatically on basis of the identification or validation of the main domains by the computer system.

According to an aspect of the invention the validation keywords are generated by removing stop words, company forms and/or words having a small size form the target name. Stop words are for example "and", "or", "is", "are", "in", "on" or the like. Company forms are "gmbh", "ag", "inc" or the like. Words having a small size, for example less than <NUM> characters are "us", "de", "eu" or the like. By the movement of stop words, company forms and/or words having a small size the determination of the second score is focused on the core of the target name so that advantageously also variations of the target name are considered within the scoring step. Preferably the validation keywords are generated by a combination of the target name with at least one organization names or entity names, in particular wherein delimiters are uses. Delimiters are for example "␣", "_", "-" or the like. A validation keyword factor is assigned for each validation keyword, whereas in particular a higher validation keyword factor is assigned for validation keywords that are a combination of the target name with at least one organization name than for validation keywords that are only based on the target name. For example, the combination of the target name "T-Mobile US" with the organization name or entity name "Deutsche Telekom" leads to the following validation keywords with the adjacent assigned validation keyword factor: "deutsche": <NUM>, "deutsche-telekom": <NUM>, "deutschetelekom": <NUM>, "deutsche telekom": <NUM>, "telekom": <NUM>, "t-mobile": <NUM>. The combination of the target name and the organization name with the higher validation keyword factor relates to a higher rating of validation keywords that are related to the organization, respectively entity.

According to an aspect of the invention the at least one second data source is a data base which contains information about domains and IP addresses, in particular an IP-Whois data base, wherein the data base entry for the main domain or a corresponding IP address is scanned for the number of appearances of the validation keywords. Preferably the data base entry is scanned which contains the organization name to which the domain is assigned. The data base stores the registered users or assignees of internet resources, such as a domain name or an IP address. By accessing the data base, the computer system gets information about the users or assignees of the respective main domain. This allows to identify whether the respective main domain is related to the target name, respectively organization or entity.

According to an aspect of the invention the at least one second data source is a certificate information of the main domain, in particular the HTTPS certificate of the website that corresponds to the main domain. The computer system gets the certificate information of the main domain by access of the server which provides the main domain. In particular the computer system gets the HTTPS certificate from the website which is related to the main domain. Preferably the certified information that comprises the organization name assigned to the domain is scanned for the number of appearances of the validation keywords. This provides advantageously a reliable identification of the main domain.

According to an aspect of the invention the at least one second data source is the domain name. The usage of the domain name itself has the effect that the computer system just has to scan the already available list of main domains. As an advantage the computer system therefore does not need to access external data sources, which can make the scoring step faster and more independent.

According to an aspect of the invention the at least one second data source is the content of the website that corresponds to the main domain, in particular the HTTP content or HTTPS content, wherein the source code of the website is scanned for the number of appearances of the validation keywords. The content of the website that corresponds to the main domain contains typically relevant information regarding the identity of the main domain itself. By scanning the source code of the website, the computer system is able to extract relevant information for identification of the main domain. Preferably the computer system accesses the server which hosts the main domain and scans the source code, in particular the source code of the HTTP content or HTTPs content.

According to an aspect of the invention the at least one second data source is the content of the imprint of the website that corresponds to the main domain, wherein the source code of the imprint is scanned for the number of appearances of the validation keywords, in particular an imprint information that comprises the organization name or entity name. The computer system uses the source code of the website of the corresponding main domain to extract the content of the imprint. For example, the computer system can extract the imprint content directly from the source code of the website or the computer system extract the link to the imprint content and uses this link to get access of the source code of the imprint content. After she extraction of the imprint content the computer system scans the source code for the number of appearances of the validation keywords. Advantageously the imprint provides isolated and more reliable information for the identification of the main domain.

According to an aspect of the invention more than one second scores are determined for each main domain and the second scores are added to the first score, wherein more than one validation keywords are generated and the respective second score is determined for each validation keyword; and/or wherein more than one second data sources are scanned for the number of validation keyword appearances and the second score is determined for each second data source. This means that the second score is determined for each combination of a second data source and a validation keyword. Therefore, the number of second scores corresponds to the multiplication of the number of validation keywords with the number of second data sources. For example, when only one second data source is used the number of second scores corresponds to the number of validation keyword, whereas when only one validation keyword is used the number of second scores corresponds to the number of second data sources. Preferably each of the determined second scores is added to the first score in order to calculate the final score for each main domain. By using several second data sources the data basis for the identification of the main domain is enlarged so that the reliability of the identification is advantageously improved. Also, the usage of the larger number of validation keywords, in particular combined validation keywords, leads to higher reliability.

According to an aspect of the invention the at least one second score is weighted differently depending on the second data source. Preferably the at least one second score of the certificate information and/or the at least one second score of the imprint is weighted higher than the at least one scores of the other second data sources. The different weighting of the second scores of the certificate information takes into account that the validity of the certificate information is reviewed by checking the corresponding signature. Therefore, the reliability of the certificate information, in particular the HTTPs certificate, is considered to be relatively, in particular in comparison to the IP-Whois database, the main domain or the website. Also, the reliability of the imprint is considered to higher reliability than in particular the content of the website itself. Preferably the different weighting is achieved by the multiplication of the validation keyword factor with a defined weighting factor, for example a factor of <NUM>. The different weighting leads advantageously to a higher reliability of the identification.

The method of the invention comprises a validation step, in which the validity of each main domain is determined on basis of a comparison of the final score of each main domain with a threshold, wherein the main domain is considered as valid if the final score is above the threshold, and wherein the main domain is considered as invalid if the final score in equal or below the threshold. The validation step based on the threshold determines for each main domain whether this main domain is valid or invalid. When the main domain is considered as valid that means that the main domain is identified to belonging to the organization or entity, whereas when the main domain is considered as invalid that it means the main domain is identified to not belonging to the organization or entity. The comparison of the final score with the threshold provides advantageously a simple and efficient way to determine whether the main domain belongs to the organization or entity, respectively whether the main domain could be identified with the organization or entity.

Preferably, if the main domain is considered to be invalid by a certain number, this main domain will be added to the blacklist. As result, in subsequent determination and identification methods this main domain will be filtered out within the filter step of the extraction step. For these main domains it is no longer necessary to determine the first and second score so that the efficiency of the method is advantageously improved.

The underlying problem is also solved by a computer system for automatic and dynamic determination and identification of main domains, configured to perform the steps described above. The computer system is preferably one physical and/or logical server (cloud service) that is configured to perform the above-described steps. In particular the computer system comprises several physical and/or logical server (cloud service), preferably deployed as computer cluster with several nodes. Preferably, the computer system comprises computing means and communication means that are configured to perform the above-mentioned steps automatically. In particular the means, preferably communication means, are configured to access the at least one first data source and the at least one second data source by using or sending an input or a query to the at least one first data source and the at least one second data source. The means of the computer system are in particular configured to search or scan the at least one first data source to obtain the URLs or domains for the generation of the search list and wherein the means are configured to search and scan the at least one second data source to obtain the number of appearances of the validation keyword within the at least one second data source.

The underlying problem is also solved by a computer program product for automatic and dynamic determination and identification of main domains belonging to an entity which, when executed by a computer system, causes the computer system to perform the above-described method steps.

In the following, preferred embodiments of the present invention are described with reference to the figures:.

Below, features of the invention are explained by way of a preferred embodiment. Rather, the features mentioned here can be combined arbitrarily into inventive embodiments, unless this is expressly excluded.

<FIG> shows a schematic overview of the method for automatic and dynamic determination of IT systems belonging to an entity, respectively company, enterprise, organization or the like. The method starts with the initial step <NUM>, wherein an initial target name is defined. The initial target name could be the name or title of the entity, e.g. "Deutsche Telekom". A user could define the initial target name by an input device of a computer system <NUM> that performs the method, or it could be defined automatically by the computer system <NUM>.

On basis of the initial target name a target name searching step <NUM> is performed, wherein a list of additional target names is generated. In order to search for the additional target names the computer system <NUM> uses the initial target name as input for a request to a first database <NUM>. The first database <NUM> is for example a merge and acquisition database, such as S&P Capital IQ, Amadeus, official register (e.g. Bundesanzeiger) or the like. By access to the first database <NUM> the computer system <NUM> retrieves subsidiaries of the entity as additional target names and saves them within the list of additional target names.

The initial target name and the additional target names are used as target names for the determination and identification for a main domain query step <NUM>, wherein a list of main domains is generated. The underlying invention relates to the main domain query step <NUM> and is preferably embedded in the method for automatic and dynamic determination of IT systems shown in <FIG>. In order to obtain and identify the main domains, the computer system <NUM> uses the target name, here the initial target name and/or the additional target names, as input for a request to at least one data source <NUM>. By access to the at least one data source <NUM> the computer system <NUM> retrieves main domains of the organization or entity. The underlying invention is described in detail with regard to <FIG>.

By usage of the queried main domains a subdomain enumeration step <NUM> is performed, wherein a list of subdomains is generated in addition to the existing list main domains. In order to enumerate the subdomains, the computer system <NUM> uses the main domains as input for a request to a third database <NUM>. The third database <NUM> is for example a certificate data base (e.g. https://crt. sh), a subdomain enumeration tool or a passive domain name server database. By using the third database <NUM> the computer system <NUM> retrieves subdomains of the entity. Subdomains are in particular lower-level domains, like "admin. de" or "test. The list of subdomains could be a part of the list of main domains, or a separate list.

The domains of the list of main domains and the list of subdomains are validated with a domain validation step <NUM>, wherein the domains are considered as valid (belonging to entity), invalid (not belonging to entity) or not determinable, when the validity could not be determined. For the determination of the validity of the domain's validation features are extracted from the domains. In addition, supportive features are extracted from the domains and evaluated by a supervised machine learning unit <NUM> in order to determine the validity of the domains. The supervised machine learning unit <NUM> is implemented within the computer system <NUM> and corresponds to a machine algorithm, for example a random forest algorithm or the like. The machine learning unit <NUM> is trained by supportive features extracted from valid domains, wherein the validity was determined on basis of the validation features. By usage of the machine learning unit <NUM> a link between the validation features <NUM> and the supportive features <NUM> is realized.

Within the domain name searching step <NUM> new main domains and/or new subdomains are searched on the basis of the valid domains of the list of main domains and/or the list of subdomains. For the search of new main domains and/or subdomains the valid domains are used as input for reverse searching techniques. Examples for these techniques are: Reverse Whois, Reverse Name Server, Reverse Mail Server, Buit-With and/or a search engine, like a Shodan Favicon Search. The found new main domains and/or new subdomains are preferably added to the list of main domains and/or the list of subdomains and validated by usage of the domain validation step <NUM>.

A list of IP addresses is generated on basis of the list the domains of the list of main domains and/or the list of subdomains within an IP address searching step <NUM>. The computer system <NUM> uses the domains as input for a fourth database <NUM> in order to obtain the corresponding IP addresses. The fourth database <NUM> is preferably a domain name system (DNS) server, wherein the IP addresses are resolved on the basis of the domains. In a preferred embodiment the validity of the IP addresses is also evaluated within the IP address searching step <NUM>. For that it is checked whether the IP address corresponds to a valid or invalid domain.

In addition, a list of netblocks or IP blocks is generated within the netblock searching step <NUM>. The computer system <NUM> uses the initial target name, the additional target names, the main domains and or the subdomains as input for a fifth database <NUM>, wherein the fifth database is preferably an IP Whois database and/or a Regional Internet Registry, like the RIPE for Europe and Middle East.

The target name searching step <NUM>, the main domain query step <NUM>, the subdomain enumeration step <NUM>, the domain validation step <NUM>, the domain name searching step <NUM>, the IP address searching step <NUM> and/or the netblock searching step <NUM> are repeated within iteration loops. The further iteration loop is stopped when no new active IT systems are found.

<FIG> shows the schematic flow chart of the method for dynamic and automatic determination and identification of main domains according to the invention.

The method starts with the target name definition step <NUM>, wherein the target name is used as input for the method. The target name is the entity (initial target name) or the name of one the subsidiaries of the entity (additional target name). For example, the entity is "Deutsche Telekom AG" and the subsidiaries are: "T-Systems", "T-Mobile US", "Slovak Telekom", "Magyar Telekom", "T-Mobile Deutschland Gmbh" or the like. The target name could be defined manually by the user or automatically by the computer system <NUM>.

Based on the target name defined in the target name definition step <NUM> an enrichment step <NUM> is performed; wherein relevant words are appended to the target name. Relevant words are in particular words that relate to the main side of the entity or organization, for example: "website, imprint", "privacy", "data protection" or the like. In context of the target name "T-Mobile US" the enriched target names are: [‴T-Mobile US" website', ‴T-Mobile US" privacy', 'T-Mobile US'] and context of the target "T-Systems" the enriched target names are: [‴T-Systems" website',‴T-Systems" privacy', 'T-Systems'].

The target name and the enriched target names are used as input for the searching step <NUM>. Within the searching step <NUM> a search list is generated by using the target name and/or the enriched target names as input or query to at least one first data source 3a, 3b. The first data source 3a, 3b is for example a merge and acquisition database or a web search engine. Each of the first data sources 3a, 3b provides list of URLs for each of the enriched target names. For the above-mentioned enriched target names of the target name "T-Systems" the search engine of Google provides the following collected URLs:.

Within the searching step <NUM> the computer system <NUM> extracts the domains of the collected URLs for each of the first data sources 3a, 3b and generates a list of domains for each of the first data sources 3a, 3b. For example, the computer system extracts the following list of domains of the target name "T-Mobile US" for the search engine of Google:
T-Mobile US: ['en. org', 'www. com', 'www. handelsblatt. org', 'www. com', 'ciso. economictimes. indiatimes. com', 'www. com', 'www. com', 'www.

Similar lists of domains or also extracted for the other first data sources, for example the search engines Yahoo, Bing or Duckduckgo.

Preferably the extracted lists of domains are aggregated to the single list of domains. The aggregated list corresponds to the search list provided by the searching step <NUM>. For the above-mentioned example, the following search list is aggregated the target name,.

The search list is used as input for the extraction step <NUM>, wherein the main domains are extracted from the search list. Preferably the extraction step <NUM> contains an additional filter step 304a, wherein the main domains that are comprised in a blacklist are removed or faded out of the list of main domains. The blacklist contains general information domains, like encyclopedias or government registers. For example, domains within the blacklist are "Wikipedia", "Bloomberg" or the like. After the extraction step <NUM> and filter step 304a the following list of main domains is generated for the above-mentioned target name.

T-Mobile US: ['telekom. com', 'handelsblatt. com', 't-mobile. com', 'indiatimes. com', 't-mobile. com', 't-mobile. com', 't-mobile. com', 't-mobile. com', 't-mobile. com', 't-mobile. com', 't-mobile. com', 't-mobile.

Within the subsequent counting step <NUM> a first score is determined for each main domain of the list of main domains provided by the extraction step <NUM>. The first score for each main domain corresponds preferably to the number of appearances within the list of main domains. For example, the main domains of the main domain list for the above-mentioned target name "T-Mobile US" have the following first scores:
T-Mobile US: {'t-mobile. com': <NUM>, 'telekom. com': <NUM>, 'handelsblatt. com': <NUM>, 'indiatimes. com': <NUM>}.

In a keyword generation step <NUM> at least one validation keyword is generated on the basis of the target name. The validation keywords are for example generated by removing stop words from the target name, wherein stop words are for example "and", "or", "is", "are", "in", "on" or the like. Also, company forms like "gmbh", "ag" or "ink" can be removed for the generation of validation keywords. In addition, words that have a small size can be removed from the target name, for example words with less than <NUM> characters like "us", "de" or "eu". In a preferred embodiment the validation keywords can also be generated by a combination of the target names with the entity or organization names, wherein for the combination preferably delimiters like "␣", "_" or "-" are used. For each of the validation keywords a validation keyword factor is assigned, wherein preferably the higher validation keyword factor is assigned for validation keywords which are a combination. For example, the validation keyword factor for a single validation keywords is <NUM>, whereas the validation keyword factor for the combination is <NUM>. Exemplary the combination of the target name "T-Mobile US" with the organization name or entity name "Deutsche Telekom" leads to the following validation keywords with the adjacent assigned validation keyword factors: T-Mobile US: {"deutsche": <NUM>, "deutsche-telekom": <NUM>, "deutschetelekom": <NUM>, "deutsche telekom": <NUM>, "telekom": <NUM>, "t-mobile": <NUM>}.

The validation keywords and the assigned validation keyword factors are used within the scoring step <NUM> to determine at least one second score for each of the main domains of the list of main domains. The second score is determined by the multiplication of the number of appearances of the corresponding validation keyword within a at least one second data source 3A, 3C, 3D, 3E with the assigned validation keyword factor.

In a preferred embodiment a step 307a is executed, wherein the second data source is a domain database 3A, like an IP-Whois database. The computer system <NUM> sends a query to the domain database 3A and scans or searches the database entry that corresponds to the main domain or the database entry that corresponds to IP address of the main domain for the validation keywords. The number of appearances of the validation keyword within the database entry is multiplied by the assigned validation keyword factor. Preferably a specific part of the database entry is scanned, for example the part which contains the organization or entity name to which the domain is assigned. Exemplary for the main domain "telekom. com" of the above-mentioned target name "T-Mobile US" the second sore is determined by scanning the database entry for the URL "www. com" or the respective IP address "<NUM>. <NUM>" of the IP-Whois database 3A for the validation keywords. An exemplary result of a query of the domain database 3A is shown below, wherein the validation keyword, the URL of the main domain, the corresponding IP address and the number of appearances of the validation keyword are listed:.

The second scores are determined for all the validation keywords by multiplying the number of appearances with the validation keyword factor. For the above example with the query "www. com" the second score for the validation keyword "deutsche" is <NUM>, the second score for the validation keyword "deutsch telekom" is <NUM> and the second score for the validation keyword "telekom" is <NUM>. The same scores are also achieved for the query "telekom. The sum of all second scores of the validation key words of step 307a is thus <NUM>. Taking into account only the step 307a the final score determined in a calculation step <NUM> would be the first score for the main domain "telekom. com", which is <NUM>, and the sum of all second scores of step 307a, which is <NUM>, leading to a final score of <NUM>. The domain database 3A is also queried for the remaining main domains of the list of main domains of the target name "T-Mobile US", which are "t-mobile. com", "handelsblatt. com" and "indiatimes. For the above example, the corresponding final scores after the step 307a are:
T-Mobile US:
check_for_equal_domains after whois analysis {'telekom. com': <NUM>, handelsblatt. com': <NUM>, 't-mobile. com': <NUM>, 'indiatimes. com': <NUM>}.

In a preferred embodiment a step 307b is executed by the computer system <NUM>, wherein the second data source is the domain name itself. The number of appearances of the validation keywords within the main domain name of the main domain list are determined within step 307b. The number of appearances of the validation keyword is multiplied with the corresponding validation keyword factor. For the above-mentioned example, the domain name "telekom. com" contains the validation keyword "telekom" which has the validation keyword factor of <NUM>, leading to a second score of <NUM>. Preferably this second score <NUM> is added to the first score of the main domain "telekom. com", which is <NUM>, and to the sum of the second scores of step 307a, which is <NUM>, leading to a final score of <NUM> for the main domain "telekom. The main domain is also queried for the remaining main domains of the list of main domains of the target name "T-Mobile US". For the above example, the corresponding final scores after the steps 307a and 307b are:
T-Mobile US:
{'telekom. com': <NUM>, 'handelsblat. com': <NUM>, 't-mobile. com':<NUM>, 'indiatimes. com': <NUM>}.

In a preferred embodiment a step 307c is executed by the computer system <NUM>, wherein the second data source is a certificate information 3B of the main domain. In particular the certificate information 3C is a HTTPS certificate of the domain/website. Preferably the part of the certificate information 3C is scanned for the number of appearances of the validation keyword that contains the organization name or the entity name to which the domain/website is assigned to. The computer system <NUM> sends a query to a server which hosts the website of the domain with the certificate information 3B, in particular the HTTPS certificate. For the above example the HTTPS certificate of the website "www. com" contains the "Deutsche Telekom IT GmbH" as assigned organization, this entry is scanned for the appearances of the validation keywords, whereas the number of appearances is multiplied with the corresponding validation keyword factor in order to determine the second score. For this example, the second score for the validation keyword "telekom" is <NUM>, for the validation keyword "deutsche" <NUM> and for the validation keyword "deutsche telekom" <NUM>. Preferably the second score is determined for all validation keywords and all second scores of the validation keywords are summed. In the above example the sum of all second scores of step 307c is <NUM>. The certificate information 3C is also queried for the remaining main domains of the main domain list of the target name "T-Mobile US"", wherein the corresponding final scores after the steps 307a, 307b and 307c are:
T-Mobile US:
{'telekom. com': <NUM>, 'handelsblatt. com': <NUM>, 't-mobile. com': <NUM>, 'indiatimes. com': <NUM>}.

In a preferred embodiment the at least one second score, respectively the keyword factor, of the certificate information 3C is whited higher than the validation keyword factors of the other second data sources 3A, 3D and 3E. For example, an additional factor of <NUM> is used for the number of appearances of validation keywords within the certificate information 3C.

In a preferred embodiment a step 307d is executed by the computer system <NUM>, wherein second source is the content of the website 3D that corresponds to the main domain. This is preferably the HTTP or HTTPS content of the website. In order to determine the number of appearances of the validation keyword within the content of the website the source code of the website is searched or scanned for the validation keywords. Preferably the computer system <NUM> obtains the source code of the website by access to the server which hosts the website of the main domain. The source code of the website 3D is searched for the number of appearances of the validation keywords. For the above-mentioned example with "telekom. com" as main domain the corresponding URL "www. com" is scanned or searched for the validation keywords leading for example to the following number of appearances:.

The validation keyword factor is preferably only added to the second score when the number of appearances exceeds a threshold, for example <NUM>. For the above example this means that the validation keyword factor of <NUM> for the validation keyword "deutsche", the validation keyword factor of <NUM> for the validation keyword "deutschtelekom" and validation keyword factor of <NUM> for the validation keyword "telekom" are added as second scores, whereas the validation keyword factor of <NUM> for the validation keyword "t-mobile" is not added because the number of appearances is below the threshold of <NUM>. As result the sum of all second scores of step 307d is <NUM> in this example, which leads to a final score of <NUM> for the main domain "telekom. com" when the steps 307a, 307b, <NUM> and 307d are executed and the scores added. The content of the website 3D is also queried for the remaining main domains of the main domain list of the target name "T-Mobile US", wherein for the above example, the corresponding final scores after the steps 307a, 307b, 307c and 307d are:
T-Mobile US:
{'telekom. com': <NUM>, 'handelsblatt. com': <NUM>, 't-mobile. com': <NUM>, 'indiatimes. com': <NUM>}.

In a preferred embodiment a step 307e is executed by the computer system <NUM>, wherein the second data source is the content of the imprint 3E of the website that corresponds to the main domain. The imprint 3E of the website is obtained by the computer system <NUM> by access to the server which hosts the website of the main domain. In particular links of the website are searched and executed in order to obtain the source code of the imprint 3E of the corresponding website. Preferably an imprint information that comprises the organization name or entity name is searched for the appearances of the validation keyword. In a preferred embodiment the at least one second score, respectively the keyword factor, of the imprint 3E is whited higher than the validation keyword factors of the other second data sources 3A, 3C and 3D.

In a calculation step <NUM> the first score of the step <NUM> and the second scores of the step <NUM> are added in order to determine the final score of the main domain. When more than one validation keywords are generated a corresponding second score is determined for each validation keyword. Also, when more than one second data sources 3A, 3C, 3D, 3E are scanned for the number of appearances of validation keywords a corresponding second score is determined for each of the scanned second data sources 3A, 3C, 3D, 3E. In the above example all second scores of the steps 307a, 307b, 307c and 307d are added to the first score of the step <NUM> in order to determine the final score of <NUM> for the validation keyword "telekom.

In a validation step <NUM> the validity of each main domain is determined by the comparison of the final score with a threshold. The main domain is considered as valid when the final score is higher than the threshold (step <NUM>), whereas the main domain is considered as invalid when the final score is equal or below the threshold (step <NUM>). When the threshold is exemplary set to <NUM>, the main domains "telekom. com" and "t-mobile. com" are considered as valid because their final scores are above <NUM>, whereas the main domains "handelsblatt. com" and "indiatimes. com" are considered as invalid because the final scores are below <NUM>. Preferably the entries of the blacklist of the additional filter step 304a are generated automatically on basis of the identification or validation of the main domains by the computer system <NUM>, wherein in particular main domains that were considered invalid a certain number of times are added to the blacklist.

Claim 1:
Method for automatic and dynamic determination of main domains belonging to an entity, comprising the following steps performed by a computer system (<NUM>):
- a searching step (<NUM>), wherein a search list is generated by using a target name as input to a at least one first data source (3a, 3b), in particular a merge and acquisition data base or a web search engine;
- an extraction step (<NUM>), wherein a list of main domains, in particular second-level domains, is extracted from the search list;
- a counting step (<NUM>), wherein a first score is determined for each main domain of the list of main domains by counting the number of the appearances within the list of main domains;
- a keyword generation step (<NUM>), wherein at least one validation keyword is generated on basis of the target name;
- a scoring step (<NUM>), wherein at least one second score is determined for each main domain of the list of main domains by multiplying the number of appearances of the at least one validation keyword within a at least one second data source (3A, 3C, 3D, 3E) with a validation keyword factor assigned to the validation keyword;
- a calculation step (<NUM>), wherein a final score is determined for each main domain as sum of the first score and the at least one second score; and
- a validation step (<NUM>), in which the validity of each main domain is determined on basis of a comparison of the final score of each main domain with a threshold, wherein the main domain is considered as valid if the final score is above the threshold (step <NUM>), and wherein the main domain is considered as invalid if the final score in equal or below the threshold (<NUM>), wherein a valid main domain is a main domain that is identified as belonging to the organization or entity, whereas an invalid main domain is a main domain that is identified as not belonging to the organization or entity.