T1185 — Browser Session Hijacking

# T1185 - Browser Session Hijacking

## SOC Recommendation
Investigate Browser Session Hijacking activity in the context of Collection: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.

## D3FEND Mappings
| D3FEND Technique | Relationship | Practical SOC Action |
|---|---|---|
| User Geolocation Logon Pattern Analysis | Detect | Monitor for User Geolocation Logon Pattern Analysis indicators relevant to this technique. |
| Network Traffic Filtering | Isolate | Apply Network Traffic Filtering to contain the blast radius once this technique is observed. |

## Investigation Steps
1. Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.
2. Check Sentinel analytics rules and incidents correlated with this technique.
3. Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource.

## Evidence to Collect
- Host or resource affected
- Account or identity involved
- Timestamp of the activity
- Related process, file, or network artifact
- Any preceding or follow-on alerts

## Response Actions
| Action | Risk | Automation Safe | Approval Required |
|---|---|---|---|
| Contain the affected host or account | Medium | No | Yes |
| Collect and preserve evidence | Low | Yes | No |

## KQL
```kql
let threshold = 5;
GWorkspaceActivityReports
| where isnotempty(UserAgentOriginal)
| summarize user_ua = makeset(UserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
| where array_length(user_ua) > threshold
| extend IPCustomEntity = SrcIpAddr
```

## Escalation Criteria
- Browser Session Hijacking activity observed on a privileged account or critical system.
- Activity follows or precedes other suspicious behaviour in the same investigation.
- Automated triage cannot confidently rule out malicious intent.

## False Positive Considerations
- Legitimate administrative or maintenance activity matching this pattern.
- Approved security testing or red team exercise.
- Known benign software producing similar telemetry.

Generated by SOC Response Atlas by Basyrix.

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• /api/techniques/T1185.json
• /api/recommendations/T1185.json
• /api/d3fend/T1185.json
• /api/mappings/T1185.json
• /api/confluence/T1185.md

Example curl:

curl https://atlas.basyrix.com/api/recommendations/T1185.json

Response:

{
  "technique_id": "T1185",
  "name": "Browser Session Hijacking",
  "priority": "high",
  "status": "draft",
  "version": "0.1.0",
  "last_reviewed": "2026-07-23",
  "generated_by": "SOC Response Atlas by Basyrix",
  "tactics": [
    "Collection"
  ],
  "platforms": [
    "Windows"
  ],
  "summary": "Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques. A specific example is when an adversary injects software into a browser that allows them to inherit cookies, HTTP sessions, and SSL client certificates of a user then use the browser as a way to pivot into an authenticated intranet...",
  "soc_recommendation": "Investigate Browser Session Hijacking activity in the context of Collection: confirm scope, affected host/identity, and whether it matches expected administrative behaviour before deciding this is benign.",
  "d3fend_mappings": [
    {
      "id": "D3-UGLPA",
      "name": "User Geolocation Logon Pattern Analysis",
      "relationship": "detect",
      "practical_action": "Monitor for User Geolocation Logon Pattern Analysis indicators relevant to this technique.",
      "tooling": [
        "Defender for Endpoint"
      ]
    },
    {
      "id": "D3-NTF",
      "name": "Network Traffic Filtering",
      "relationship": "isolate",
      "practical_action": "Apply Network Traffic Filtering to contain the blast radius once this technique is observed.",
      "tooling": [
        "Sentinel",
        "Defender for Endpoint"
      ]
    }
  ],
  "investigation_steps": {
    "microsoft": [
      "Review Defender for Endpoint / Defender XDR alerts and timeline for the affected host or identity.",
      "Check Sentinel analytics rules and incidents correlated with this technique.",
      "Review Entra ID sign-in and audit logs if the technique involves an identity or cloud resource."
    ],
    "generic": [
      "Confirm whether the observed browser session hijacking activity matches expected administrative or application behaviour.",
      "Identify the host, account, or resource where the activity occurred and its business criticality.",
      "Check for related alerts before and after this activity to reconstruct the broader intrusion timeline.",
      "Real detection reference: \"GWorkspace - Multiple user agents for single source\" -- Detects requests with different user agents from one source in short timeframe.'"
    ]
  },
  "evidence_to_collect": [
    "Host or resource affected",
    "Account or identity involved",
    "Timestamp of the activity",
    "Related process, file, or network artifact",
    "Any preceding or follow-on alerts"
  ],
  "response_actions": [
    {
      "name": "Contain the affected host or account",
      "category": "Containment",
      "risk": "Medium",
      "automation_safe": false,
      "approval_required": true,
      "tool": "Defender for Endpoint / Entra ID",
      "notes": "Requires approval -- confirm malicious intent before isolating a host or disabling an account."
    },
    {
      "name": "Collect and preserve evidence",
      "category": "Investigation",
      "risk": "Low",
      "automation_safe": true,
      "approval_required": false,
      "tool": "Defender for Endpoint",
      "notes": "Safe -- read-only evidence collection."
    }
  ],
  "queries": {
    "kql": [
      {
        "name": "6ff0e16e-5999-11ec-bf63-0242ac130002 — GWorkspace - Multiple user agents for single source",
        "description": "Detects requests with different user agents from one source in short timeframe.' (Source: Microsoft's official Azure-Sentinel Detections (MIT licensed).)",
        "query": "let threshold = 5;\nGWorkspaceActivityReports\n| where isnotempty(UserAgentOriginal)\n| summarize user_ua = makeset(UserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)\n| where array_length(user_ua) > threshold\n| extend IPCustomEntity = SrcIpAddr"
      }
    ],
    "spl": [],
    "esql": [
      {
        "name": "f1f3070e-045c-4e03-ae58-d11d43d2ee51 — Manual Loading of a Suspicious Chromium Extension",
        "description": "(EQL) Detects the manual loading of a Chromium-based browser extension via command line arguments. This activity is suspicious and could indicate a threat actor loading a malicious extension to persist or collect browsing secrets such as cookies and authentication tokens. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "process where host.os.type == \"macos\" and event.action == \"exec\" and\n  process.name in (\"Google Chrome\", \"Brave Browser\", \"Microsoft Edge\") and\n  process.args like \"--load-extension=/*\" and\n  not (process.args like \"--load-extension=/Users/*/Library/Application Support/Cypress/*\" and\n       process.parent.executable like (\"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome\",\n                                        \"/Users/*/Library/Caches/Cypress/*/Cypress.app/Contents/MacOS/Cypress\")) and\n  not process.parent.executable like (\"/opt/homebrew/Caskroom/chromedriver/*/chromedriver\",\n                                    \"/Applications/Cypress.app/Contents/MacOS/Cypress\",\n                                    \"/usr/local/bin/chromedriver\")"
      },
      {
        "name": "46b01bb5-cff2-4a00-9f87-c041d9eab554 — Browser Process Spawned from an Unusual Parent",
        "description": "(EQL) Identifies instances where a browser is launched with remote debugging, headless automation, or minimal arguments from an unusual parent process. This may indicate an attempt to broker or tamper with a browser session for credential theft. (Source: Elastic's official detection-rules repository (Elastic License v2).)",
        "query": "process where host.os.type == \"windows\" and event.type == \"start\" and\n  process.name : (\"chrome.exe\", \"msedge.exe\") and\n  process.parent.executable != null and\n  (\n    process.command_line : (\n            \"\\\"C:\\\\Program Files (x86)\\\\Microsoft\\\\Edge\\\\Application\\\\msedge.exe\\\"\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\"\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\" --headless --disable-logging --log-level=3 --v=0\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\" --headless --log-level=3\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\" --headless\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\" --remote-debugging-port=922? --profile-directory=\\\"Default\\\"*\",\n            \"\\\"C:\\\\Program Files\\\\Google\\\\Chrome\\\\Application\\\\chrome.exe\\\" --headless --restore-last-session --remote-debugging-port=45452*\"\n    ) or\n    (process.args : \"--remote-debugging-port=922?\" and process.args : \"--window-position=-*,-*\")\n  ) and\n  not process.parent.executable :\n                         (\"C:\\\\Windows\\\\explorer.exe\",\n                          \"C:\\\\Program Files (x86)\\\\*.exe\",\n                          \"C:\\\\Program Files\\\\*.exe\",\n                          \"C:\\\\Windows\\\\System32\\\\rdpinit.exe\",\n                          \"C:\\\\Windows\\\\System32\\\\sihost.exe\",\n                          \"C:\\\\Windows\\\\System32\\\\RuntimeBroker.exe\",\n                          \"C:\\\\Windows\\\\System32\\\\SECOCL64.exe\")"
      }
    ]
  },
  "automation": {
    "safe": [
      "Add recommendation as Sentinel incident comment.",
      "Run enrichment queries.",
      "Create ServiceNow SecOps task."
    ],
    "approval_required": [
      "Contain or disable the affected host/account.",
      "Any change to production configuration."
    ]
  },
  "escalation_criteria": [
    "Browser Session Hijacking activity observed on a privileged account or critical system.",
    "Activity follows or precedes other suspicious behaviour in the same investigation.",
    "Automated triage cannot confidently rule out malicious intent."
  ],
  "false_positive_considerations": [
    "Legitimate administrative or maintenance activity matching this pattern.",
    "Approved security testing or red team exercise.",
    "Known benign software producing similar telemetry."
  ],
  "confluence": {
    "title": "T1185 - Browser Session Hijacking Response Guidance",
    "labels": [
      "mitre",
      "attack",
      "d3fend",
      "secops",
      "basyrix"
    ],
    "sections": [
      "summary",
      "d3fend_mappings",
      "investigation_steps",
      "response_actions",
      "queries",
      "automation",
      "escalation_criteria",
      "false_positive_considerations"
    ]
  }
}