Detection of Web Session Cookie Theft via File, Memory, and Network Artifacts

ID: DET0509
Domains: Enterprise
Analytics: AN1402, AN1403, AN1404, AN1405, AN1406
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1402

Detects suspicious access to browser session cookie storage (e.g., Chrome’s Cookies SQLite DB) or memory reads of browser processes. Anomalous injection or memory dump utilities targeting browser processes such as chrome.exe, firefox.exe, or msedge.exe.

Log Sources
Data Component Name Channel
Process Access (DC0035) WinEventLog:Sysmon EventCode=10
File Modification (DC0061) WinEventLog:Sysmon EventCode=2
Process Creation (DC0032) WinEventLog:Security EventCode=4688
Mutable Elements
Field Description
TargetProcessList Monitored browsers (e.g., chrome.exe, firefox.exe)
AccessToolList Suspicious tools used for injection or memory access (e.g., mimikatz, procdump)
TargetCookiePaths Locations of cookie stores like `AppData\Local\Google\Chrome\User Data\Default\Cookies`

AN1403

Detects access to known browser cookie files (e.g., ~/.mozilla/firefox/*.default/cookies.sqlite, ~/.config/google-chrome/) and suspicious reads of browser memory via /proc/[pid]/mem or ptrace.

Log Sources
Data Component Name Channel
File Access (DC0055) auditd:SYSCALL open or read to browser cookie storage
Process Access (DC0035) auditd:SYSCALL ptrace syscall or access to /proc/*/mem
Mutable Elements
Field Description
CookieFilePatterns Regex paths to known browser cookie locations
TimeWindow Correlated time range between cookie read and web upload or process injection
BrowserProcPatterns Expected names for browser processes being accessed

AN1404

Detects unauthorized access to browser cookie paths (e.g., ~/Library/Application Support/Google/Chrome/Default/Cookies) or task_for_pid/vm_read calls to Safari/Chrome memory space.

Log Sources
Data Component Name Channel
Process Access (DC0035) macos:unifiedlog vm_read, task_for_pid, or file open to cookie databases
File Access (DC0055) fs:fsusage file open for known browser cookie paths
Mutable Elements
Field Description
TargetBrowserList List of processes considered web browsers on macOS
BrowserCookiePathList Cookie database paths specific to each browser

AN1405

Detects automation macros or VBA scripts in documents that access browser file paths, read cookie data, or attempt to exfiltrate browser session tokens over HTTP.

Log Sources
Data Component Name Channel
Application Log Content (DC0038) m365:unified RunMacro
File Modification (DC0061) WinEventLog:Sysmon EventCode=2
Mutable Elements
Field Description
MacroTargetPath Files or directories macros are attempting to access
HTTPDestinationIPList List of IPs or domains that are uncommon for macro-based HTTP POSTs

AN1406

Detects use of session cookies or authentication tokens from unusual user agents or locations. Identifies token reuse without reauthentication or attempts to bypass MFA using previously stolen cookies.

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) saas:googleworkspace login with reused session token and mismatched user agent or IP
Logon Session Creation (DC0067) saas:okta session.token.reuse
Mutable Elements
Field Description
TokenReuseTimeWindow Max allowed delta between token issuance and second use
UserAgentAnomalyScore Deviation score from normal browser/device fingerprint
GeoLocationAnomalyScore Deviation in IP region or ASN per user profile