Query: SIEM correlation: reconnaissance activity consistent with Network Security Appliances
Matching passage: T1590.006 Network Security Appliances. Tactics: reconnaissance. Description: Adversaries may gather information about the victim's network security appliances that can be used during targeting. Information about network security appliances may include a variety of details, such as the existence and specifics of deployed firewalls, content filters, and proxies/bastion hosts. Adversaries may also target information about victim network-based intrusion detection systems (NIDS) or other appliances related to defensive cybersecurity operations. Adversaries may gather this information in various ways, such as direct collection actions via [Active Scanning](https://attack.mitre.org/techniques/T1595) or [Phishing for Information](https://attack.mitre.org/techniques/T1598).(Citation: Nmap Firewalls NIDS) Information about network security appliances may also be exposed to adversaries via online or other accessible data sets (ex: [Search Victim-Owned Websites](https://attack.mitre.org/techniques/T1594)). Gathering this information may reveal opportunities for other forms of reconnaissance (ex: [Search Open Technical Databases](https://attack.mitre.org/techniques/T1596) or [Search Open Websites/Domains](https://attack.mitre.org/techniques/T1593)), establishing operational resources (ex: [Develop Capabilities](https://attack.mitre.org/techniques/T1587) or [Obtain Capabilities](https://attack.mitre.org/techniques/T1588)), and/or initial access (ex: [External Remote Services](https://attack.mitre.org/techniques/T1133)).
Near-miss passage: T1590.002 DNS. Tactics: reconnaissance. Description: Adversaries may gather information about the victim's DNS that can be used during targeting. DNS information may include a variety of details, including registered name servers as well as records that outline addressing for a target’s subdomains, mail servers, and other hosts. DNS MX, TXT, and SPF records may also reveal the use of third party cloud and SaaS providers, such as Office 365, G Suite, Salesforce, or Zendesk.(Citation: Sean Metcalf Twitter DNS Records) Adversaries may gather this information in various ways, such as querying or otherwise collecting details via [DNS/Passive DNS](https://attack.mitre.org/techniques/T1596/001). DNS information may also be exposed to adversaries via online or other accessible data sets (ex: [Search Open Technical Databases](https://attack.mitre.org/techniques/T1596)).(Citation: DNS Dumpster)(Citation: Circl Passive DNS) Gathering this information may reveal opportunities for other forms of reconnaissance (ex: [Search Open Technical Databases](https://attack.mitre.org/techniques/T1596), [Search Open Websites/Domains](https://attack.mitre.org/techniques/T1593), or [Active Scanning](https://attack.mitre.org/techniques/T1595)), establishing operational resources (ex: [Acquire Infrastructure](https://attack.mitre.org/techniques/T1583) or [Compromise Infrastructure](https://attack.mitre.org/techniques/T1584)), and/or initial access (ex: [External Remote Services](https://attack.mitre.org/techniques/T1133)). Adversaries may also use DNS zone transfer (DNS query type AXFR) to collect all records from a misconfigured DNS server.(Citation: Trails-DNS)(Citation: DNS-CISA)(Citation: Alexa-dns)