Name:Cisco SA - Access to Anonymizer Services id:a7c8613a-92e2-4232-b64d-bd39d33dee8b version:1 date:None author:Mahamudul Chowdhury, Bhavin Patel, Splunk status:production type:Anomaly Description:This analytic detects attempts to access proxy-evasion or anonymizer services using Cisco Secure Access DNS and secure web proxy telemetry.
Users who reach anonymizer or proxy-evasion infrastructure are often trying to bypass corporate controls such as secure web gateway inspection, DLP monitoring, CASB visibility, and threat-detection systems. These services frequently establish encrypted tunnels that hide subsequent traffic from inspection.
Early identification helps security teams spot circumvention attempts before potential data exfiltration or follow-on malicious activity. Correlating DNS resolution and proxy session data strengthens confidence that access was intentional.
Data_source:
-Cisco Secure Access DNS
search:`cisco_secure_access_dns` action = "allowed" category= "*anonymizer*" | fillnull | stats count min(_time) as firstTime max(_time) as lastTime values(domain) as domain values(query) as query values(reply_code) as reply_code values(record_type) as record_type by src_ip src_external_ip user identity_type action category sourcetype | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `cisco_sa___access_to_anonymizer_services_filter`
how_to_implement:Ingest Cisco Secure Access DNS and proxy events into Splunk using the Splunk Add-on for Cisco Security Cloud (https://splunkbase.splunk.com/app/7404).
Update the `cisco_secure_access_dns` macro so it resolves to the indexes, sources, and sourcetypes used in your environment.
known_false_positives:Security research, approved privacy tools, or mis-categorized destinations may appear as anonymizer traffic. Tune this analytic with the filter macro or allow-lists for known-good users, networks, and domains after validating business justification.
References: -https://attack.mitre.org/techniques/T1090/003 drilldown_searches: name:'View the detection results for user $user$ and source $src_ip$' search:'%original_detection_search% | search user = "$user$" src_ip = "$src_ip$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for $user$' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'7d' latest_offset:'0' analytic_story:['Cisco Secure Access Analytics']
