Detect Browser Session Hijacking in CrowdStrike LogScale
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 process that allows them to inherit cookies, HTTP sessions, and SSL client certificates of a user, then uses the browser as a pivot into an authenticated intranet. Executing browser-based behaviors such as pivoting may require specific process permissions, such as SeDebugPrivilege and/or high-integrity/administrator rights. Another technique involves redirecting browser traffic through an adversary-controlled proxy injected into the browser process, allowing session impersonation without modifying user-visible traffic. Malware families such as TrickBot, Dridex, IcedID, QakBot, and Cobalt Strike implement browser pivoting and web inject techniques to steal banking credentials, session tokens, and SSL certificates.
MITRE ATT&CK
- Tactic
- Collection
- Technique
- T1185 Browser Session Hijacking
- Canonical reference
- https://attack.mitre.org/techniques/T1185/
LogScale Detection Query
// Detection 1: Suspicious process injection into browser processes
#event_simpleName = "CreateRemoteThreadV2" OR #event_simpleName = "WriteProcessMemory" OR #event_simpleName = "SetThreadContext"
| TargetImageFileName = /(?i)(chrome|msedge|firefox|iexplore|brave|opera|microsoftedge)\.exe$/
| SourceImageFileName != /(?i)(chrome|msedge|firefox|MsMpEng|WerFault|WerFaultSecure|csrss|dwm|taskmgr)\.exe$/
| eval InjectionMethod = case(
#event_simpleName = "CreateRemoteThreadV2", "Remote thread injection",
#event_simpleName = "WriteProcessMemory", "Memory write injection",
#event_simpleName = "SetThreadContext", "Thread context hijacking",
"Unknown"
)
| table _time, ComputerName, UserName, InjectionMethod, SourceImageFileName, TargetImageFileName, TargetProcessId, SourceProcessId
| sort _time desc
// Detection 2: Suspicious DLL loads inside browser processes (union)
OR
#event_simpleName = "ClassifiedModuleLoad"
| ImageFileName = /(?i)(chrome|msedge|firefox|iexplore|brave|opera)\.exe$/
| NOT ModuleFilePath = /(?i)(\\Program Files\\(Google\\Chrome|Mozilla Firefox|Microsoft\\Edge)|\\Windows\\(System32|SysWOW64|WinSxS))/
| NOT ModuleFilePath = /(?i)(d3d|opengl|vulkan|nvog|atig|ig[0-9])/
| eval InjectionMethod = "Suspicious module load in browser"
| table _time, ComputerName, UserName, InjectionMethod, ImageFileName, ModuleFilePath, ModuleImageFilePath
| sort _time descDetects browser session hijacking in CrowdStrike Falcon LogScale using Falcon event types for remote thread creation, memory writes, and thread context modification targeting browser processes. Also detects suspicious DLL/module loads within browser processes from non-standard paths.
Data Sources
Required Tables
False Positives & Tuning
- CrowdStrike sensor itself may generate events when performing process inspection for threat detection
- Third-party AV or EDR products that co-exist with Falcon and access browser processes
- Legitimate browser helper objects or extensions that load as DLLs from custom enterprise software directories
- IT operations tooling such as BigFix or Tanium that may access browser process memory for inventory
- Browser-based RPA tools that instrument browser processes programmatically
Other platforms for T1185
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Browser Process Enumeration and Handle Open (ReadVM Access)
Expected signal: Sysmon EventCode=10 (ProcessAccess): SourceImage=powershell.exe, TargetImage=<browser>.exe, GrantedAccess=0x10 (PROCESS_VM_READ), CallTrace will show the kernel32.dll and ntdll.dll call stack. MDE DeviceEvents ActionType=OpenProcessApiCall with FileName=<browser>.exe, InitiatingProcessFileName=powershell.exe.
- Test 2Chrome Cookie Database Exfiltration via File Copy
Expected signal: Sysmon EventCode=11 (FileCreate): TargetFilename=%TEMP%\argus_test_cookies_*.db, Image=powershell.exe. Sysmon EventCode=1 (ProcessCreate): powershell.exe with command line referencing LOCALAPPDATA\Google\Chrome\User Data. MDE DeviceFileEvents with ActionType=FileCreated, FileName=argus_test_cookies_*.db, InitiatingProcessFileName=powershell.exe.
- Test 3Browser Proxy Configuration via Registry (Browser Pivot Simulation)
Expected signal: Sysmon EventCode=13 (RegistryValueSet): TargetObject=HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyServer, Details=127.0.0.1:4444, Image=powershell.exe. Second EventCode=13 for ProxyEnable=1. MDE DeviceRegistryEvents with ActionType=RegistryValueSet, RegistryValueName=ProxyServer, RegistryValueData=127.0.0.1:4444.
- Test 4CreateRemoteThread Simulation into Browser Process (Benign Payload)
Expected signal: Sysmon EventCode=8 (CreateRemoteThread): SourceImage=powershell.exe, TargetImage=<browser>.exe, StartAddress=<kernel32!Sleep address>, StartModule=C:\Windows\System32\kernel32.dll, StartFunction=Sleep. MDE DeviceEvents ActionType=CreateRemoteThreadApiCall, FileName=<browser>.exe, InitiatingProcessFileName=powershell.exe. Security Event ID 4688 for the PowerShell process if command line auditing is enabled.
References (10)
- https://attack.mitre.org/techniques/T1185/
- https://en.wikipedia.org/wiki/Man-in-the-browser
- https://www.cobaltstrike.com/help-browser-pivoting
- https://web.archive.org/web/20210825130434/https://cobaltstrike.com/downloads/csmanual38.pdf
- https://www.icebrg.io/blog/malicious-chrome-extensions-enable-criminals-to-impact-over-half-a-million-users-and-global-businesses
- https://www.fidelissecurity.com/threatgeek/threat-intelligence/trickbot-we-missed-you-dyre/
- https://securityintelligence.com/trickbot-new-banking-trojan-delivers-credential-stealing-attacks/
- https://learn.microsoft.com/en-us/defender-endpoint/advanced-hunting-deviceevents-table
- https://learn.microsoft.com/en-us/sysinternals/downloads/sysmon
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1185/T1185.md
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