# Vulnerability Assessment of Sensor Systems
## 3 Sensor System Vulnerability Assessment Method (SVAM)
### The Solution
#### 3.2.2 Modeling of Input and Output Data of Elementary Processes  
During the vulnerability assessment, huge and diversified data assets (structured or unstructured) should be managed. Such data can be found in evaluation evidences provided by developers, in documents developed by the Common Criteria community around the world, in scientific and technical publications, in internet services, etc. Evaluators need preselected information of good quality to make evaluation decisions. The SVAM organizes these data around elementary evaluation processes. Thedata are identified and specified as knowledge bases developed on the ontology basis. Two groups of knowledge bases (KB) are distinguished:  
* General-purpose KB containing commonly used knowledge, used for any evaluation project run in ITSEF, e.g., _CCtaxonomy_, _InfoSourceTaxonomy_, _CEMattackTaxonomy_, they are marked orange in Figure 1;
* Project-specific KB containing knowledge acquired and used in the given IT product evaluation (marked green in Figure 1), e.g., _PotentialVulnerability_PV_, _ApplicableVulnerability_AV_.  
_CCtaxonomy_ expresses the taxonomy used to classify all evaluated IT products and protection profiles [6]. It ensures compatibility with international products' knowledge bases and allows one to identify a product similar to the evaluated one and, indirectly, find its potential vulnerabilities.  
_CEMattackTaxonomy_ is an implementation of attack categories (and subcategories), such as bypassing, tampering, direct attacks, monitoring, and misuse, as proposed in CEM/B2.1 [29]. This KB includes all known and possible attacks (specified in the CC style: threat agent, exploited vulnerability, adverse action, impact).  
_InfoSourceTaxonomy_ represents all possible sources of information where potential TOE-related vulnerabilities can be found. These sources are diversified and external.  
_VulRelatlssue_VRI_ is used to orientate the potential vulnerabilities search in the external information sources (EPP2-2). _AreaOfConcern_AOC_ does the same but with respect to potential vulnerabilities hidden in the TOE evaluation evidences (EPP3-2). _VulRelatlssue_VRI_ includes items of different categories represented by keywords, characterizing the TOE and its security. _AreaOfConcern_AOC_ points out suspected areas of TOE design where vulnerabilities may occur, e.g., solutions too complicated or based on unproven technologies.  
The _PotentialVulnerability_PV_ knowledge base embraces identified potential vulnerabilities resulting from the search for external sources or analyses of the vulnerability-relevant items in evidences. Concurrently, possible attack scenarios exploiting potential vulnerabilities are identified and placed into the _AttackScenario_AS_ knowledge base. Both these KBs are analyzed (EEP3-3) in terms of whether each potential vulnerability is relevant to the TOE's operational environment. Those that are \"applicable\" are included in the _ApplicableVulnerability_AV_ knowledge base, forming the basis for further analyses and penetration tests. Penetration tests, experimentally confirming if particular vulnerabilities are exploitable or not, are used to develop the ultimate AVA_VAN evaluation decision. The _PenetrationTest_PT_ knowledge base includes tests and their results.