Detect Steal Web Session Cookie in Google Chronicle
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials. Web applications and services often use session cookies as an authentication token after a user has authenticated to a website. Cookies are often valid for an extended period of time, even if the web application is not actively used. Session cookies can be found on disk in browser profile directories (SQLite databases), in the process memory of the browser, and in network traffic to remote systems. Tools such as Evilginx2 and Muraena act as adversary-in-the-middle proxies to capture session cookies from victims directed to phishing domains without the victim's endpoint ever being directly compromised. Malware families including Raccoon Stealer, QakBot, Spica, CookieMiner, Grandoreiro, and EVILNUM specifically target browser cookie stores for theft. Stolen session cookies can bypass multi-factor authentication by reusing authenticated sessions, enabling account takeover without requiring credentials.
MITRE ATT&CK
- Tactic
- Credential Access
- Technique
- T1539 Steal Web Session Cookie
- Canonical reference
- https://attack.mitre.org/techniques/T1539/
YARA-L Detection Query
rule t1539_steal_web_session_cookie {
meta:
author = "Argus Detection Engineering"
description = "Detects non-browser processes accessing browser session cookie stores or credential databases, indicating potential session cookie theft (T1539)"
severity = "HIGH"
mitre_attack_tactic = "Credential Access"
mitre_attack_technique = "T1539"
reference = "https://attack.mitre.org/techniques/T1539/"
version = "1.0"
events:
$file_access.metadata.event_type = "FILE_OPEN"
$file_access.principal.hostname = $hostname
$file_access.principal.process.file.full_path = $proc_path
(
re.regex($file_access.target.file.full_path,
`(?i)(Chrome.User Data|Edge.User Data|Firefox.Profiles|BraveSoftware.Brave-Browser|Opera.Software.Opera.Stable|Vivaldi.User Data)`) and
re.regex($file_access.target.file.full_path,
`(?i)([\\/]Cookies$|cookies\.sqlite(-wal)?$|[\\/]Local State$|[\\/]Login Data$)`)
)
not re.regex($file_access.principal.process.file.full_path,
`(?i)(\\chrome\.exe|\\msedge\.exe|\\firefox\.exe|\\brave\.exe|\\opera\.exe|\\vivaldi\.exe|\\chromium\.exe|\\msedgewebview2\.exe|\\MsMpEng\.exe|\\SearchIndexer\.exe|\\SgrmBroker\.exe|\\backgroundTaskHost\.exe|\\WerFault\.exe|\\svchost\.exe|\\TiWorker\.exe|\\TrustedInstaller\.exe)`)
condition:
$file_access
}Chronicle YARA-L 2.0 rule detecting non-browser processes performing file open operations against browser session cookie stores and saved credential databases across Chrome, Edge, Firefox, Brave, Opera, and Vivaldi. Uses UDM file event model with regex matching on full file paths and process image paths, excluding known-legitimate browser and system processes.
Data Sources
Required Tables
False Positives & Tuning
- Google Chrome or Edge update processes (GoogleUpdate.exe, MicrosoftEdgeUpdate.exe) that access User Data directories during in-place browser updates — add update helper executables to the exclusion regex
- Enterprise password manager integrations (e.g., LastPass binary component, Keeper desktop app) that read browser cookie directories to detect active sessions for autofill context
- System imaging or forensic tools run by IT administrators during incident response or routine audits — these should be detected but triaged as authorized activity
Other platforms for T1539
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 1Copy Chrome Cookie Database via CMD
Expected signal: Sysmon Event ID 11 (FileCreate): TargetFilename=%TEMP%\df00tech_test_cookies.db, Image=cmd.exe. DeviceFileEvents: ActionType=FileCreated, FileName=df00tech_test_cookies.db, FolderPath containing Chrome\User Data, InitiatingProcessFileName=cmd.exe. The source Cookies file read will appear as a separate FileAccess event for the Cookies file initiated by cmd.exe.
- Test 2Extract Chrome Cookies and Local State via PowerShell
Expected signal: Sysmon Event ID 1: powershell.exe Process Create with CommandLine containing Chrome\User Data and Copy-Item. Sysmon Event ID 11: Two FileCreate events — TargetFilename containing df00tech_chrome\LocalState and df00tech_chrome\Cookies, Image=powershell.exe. DeviceFileEvents: Two file access events for Local State and Cookies files, InitiatingProcessFileName=powershell.exe.
- Test 3Read Firefox Cookie Database via sqlite3
Expected signal: Sysmon Event ID 1: sqlite3.exe Process Create with CommandLine containing Firefox\Profiles, cookies.sqlite, and SELECT. Sysmon Event ID 11: TargetFilename=%TEMP%\df00tech_ff_cookies.txt, Image=sqlite3.exe. DeviceProcessEvents: FileName=sqlite3.exe, ProcessCommandLine contains moz_cookies. DeviceFileEvents: sqlite3.exe accessing cookies.sqlite within Firefox Profiles path.
- Test 4Linux Firefox Cookie Theft via File Copy
Expected signal: Linux auditd: syscall=openat with path containing .mozilla/firefox and cookies.sqlite, and syscall=open/write for /tmp/df00tech_ff_linux_cookies.sqlite. Syslog/auditd: process cp accessing Firefox profile path. Linux EDR agents: file access event for cookies.sqlite initiated by cp process.
References (10)
- https://attack.mitre.org/techniques/T1539/
- https://wunderwuzzi23.github.io/blog/passthecookie.html
- https://github.com/kgretzky/evilginx2
- https://github.com/muraenateam/muraena
- https://unit42.paloaltonetworks.com/mac-malware-steals-cryptocurrency-exchanges-cookies/
- https://securelist.com/project-tajmahal/90240/
- https://krebsonsecurity.com/2023/05/discord-admins-hacked-by-malicious-bookmarks/
- https://blog.talosintelligence.com/roblox-scam-overview/
- https://learn.microsoft.com/en-us/microsoft-365/security/defender-endpoint/advanced-hunting-devicefileevents-table
- https://learn.microsoft.com/en-us/azure/azure-monitor/reference/tables/signinlogs
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