Detect Web Session Cookie in CrowdStrike LogScale
Adversaries steal and reuse valid web session cookies to authenticate to web applications and cloud services, effectively bypassing multi-factor authentication. Because session cookies represent a completed authentication event, they allow adversaries to impersonate users without knowing credentials or possessing their MFA device. Cookies are commonly obtained via adversary-in-the-middle (AiTM) phishing frameworks such as Evilginx2, Modlishka, or Muraena, which proxy the legitimate login flow and capture the post-MFA session token in real time. Once imported into an attacker-controlled browser or HTTP client, the stolen cookie grants full access to the victim's SaaS applications, cloud consoles, and email for the lifetime of the session. Star Blizzard (APT29 affiliate) has used this technique via EvilGinx to compromise email accounts protected by MFA.
MITRE ATT&CK
- Tactic
- Defense Evasion Lateral Movement
- Sub-technique
- T1550.004 Web Session Cookie
- Canonical reference
- https://attack.mitre.org/techniques/T1550/004/
LogScale Detection Query
// T1550.004 — Web Session Cookie Theft Detection in CrowdStrike LogScale
// Focuses on Identity Protection events and OAuth token abuse patterns
// Detection Path 1: Impossible Travel via Identity Events
#event_simpleName=UserLogon OR #event_simpleName=OAuthTokenCreated
| UserId != ""
| GeoCountry != ""
| table([_time, UserId, UserPrincipalName, SrcIP, GeoCountry, GeoCity, ApplicationName, AuthenticationResult, AuthenticationType, CorrelationId])
| groupBy([UserId], function=[
collect([GeoCountry], multival=true, limit=100),
collect([SrcIP], multival=true, limit=100),
collect([ApplicationName], multival=true, limit=100),
min(_time, as=firstSeen),
max(_time, as=lastSeen),
count(as=signinCount)
])
| UniqueCountries := array:length(GeoCountry[])
| WindowSeconds := lastSeen - firstSeen
| ImpossibleTravel := if(UniqueCountries > 1 AND WindowSeconds < 3600, then=1, else=0)
| where ImpossibleTravel == 1
| sort(lastSeen, order=desc)
// Detection Path 2: MFA Bypass via Cookie/Token Reuse (Identity Protection)
// Run separately or union with path 1
#event_simpleName=IdentityProtectionEvent OR #event_simpleName=OAuthTokenCreated
| AuthenticationRequirement = "singleFactorAuthentication"
| (
match(field=AuthStepResultDetail, regex="(?i)(previously satisfied|token broker|existing token)", strict=false)
OR match(field=TokenIssuerType, regex="(?i)(azuread|oauth)", strict=false)
)
| match(field=ApplicationName, regex="(?i)(microsoft 365|office 365|azure portal|teams|sharepoint|onedrive|exchange|outlook)", strict=false)
| table([_time, UserId, UserPrincipalName, SrcIP, GeoCountry, GeoCity, ApplicationName, AuthenticationRequirement, AuthStepResultDetail, RiskLevel, CorrelationId])
| eval DetectionType="MFABypassViaCookie"
| sort(_time, order=desc)CrowdStrike LogScale CQL detection for T1550.004 using two parallel queries against Falcon Identity Threat Protection event types. The first query aggregates UserLogon and OAuthTokenCreated events by user, detecting impossible travel when the same user authenticates from multiple distinct countries within a 3600-second window — a signature of AiTM-captured session cookie replay. The second query directly matches identity protection events where authentication completed with single-factor authentication via token broker or existing token satisfaction on Microsoft 365/Azure applications, indicating stolen post-MFA session cookie import. Requires Falcon Identity Threat Protection module.
Data Sources
Required Tables
False Positives & Tuning
- CrowdStrike Falcon Identity connector may not have full visibility into Azure AD authentication details such as AuthStepResultDetail unless the Identity Threat Protection module is fully deployed and integrated with Azure AD, leading to incomplete detection coverage rather than false positives
- Legitimate OAuth application registrations performing daemon or background authentication using existing refresh tokens on behalf of users, which produce OAuthTokenCreated events that match the single-factor cookie satisfaction pattern
- Users working across multiple corporate locations in different countries (e.g., UK and Ireland offices, US border regions) where legitimate same-day travel produces impossible travel signals within the detection window
Other platforms for T1550.004
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 1Extract Chrome Session Cookies Using SQLite (Windows)
Expected signal: Sysmon Event ID 11 (File Create): Target image %TEMP%\stolen_cookies.db created by cmd.exe or powershell.exe. Sysmon Event ID 1 (Process Create): powershell.exe with CommandLine referencing 'SQLiteConnection' and 'Cookies'. Sysmon Event ID 10 (Process Access): If Chrome is running, file access conflict may be logged. Security Event ID 4663 if file auditing is enabled on Chrome profile directories.
- Test 2Replay Stolen Session Cookie via Python Requests
Expected signal: Network connection from python3 to httpbin.org on port 443. Linux audit log (auditd): SYSCALL record for socket/connect from python3 process. Syslog/EDR network telemetry showing python3 making outbound HTTPS connections with cookie headers in the User-Agent matching Windows browser patterns (OS mismatch indicator).
- Test 3Import Cookie to Browser via EditThisCookie and Access Authenticated Session
Expected signal: Sysmon Event ID 1: python3.exe or playwright process spawned with CDP flags. Sysmon Event ID 3: Network connection from chromium subprocess to httpbin.org on port 443. Sysmon Event ID 23 (File Delete) or 11 (File Create) for Playwright browser cache. Security Event ID 4688 if process creation auditing enabled.
- Test 4Simulate AiTM Cookie Theft Detection via Impossible Travel Pattern
Expected signal: Azure AD Sign-in Logs (SigninLogs): Two non-interactive token use events for the authenticated user against Microsoft Graph within seconds. OfficeActivity or CloudAppEvents: MailItemsAccessed or ListMessages operation from the Graph API call. Azure AD audit logs: Token issued and used for mail access.
References (10)
- https://attack.mitre.org/techniques/T1550/004/
- https://wunderwuzzi23.github.io/blog/passthecookie.html
- https://unit42.paloaltonetworks.com/mac-malware-steals-cryptocurrency-exchanges-cookies/
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-347a
- https://learn.microsoft.com/en-us/azure/active-directory/reports-monitoring/concept-sign-ins
- https://learn.microsoft.com/en-us/microsoft-365/security/defender/advanced-hunting-cloudappevents-table
- https://learn.microsoft.com/en-us/microsoft-365/compliance/audit-mailitemsaccessed
- https://github.com/kgretzky/evilginx2
- https://www.microsoft.com/en-us/security/blog/2022/07/12/from-cookie-theft-to-bec-attackers-use-aitm-phishing-sites-as-entry-point-to-further-financial-fraud/
- https://techcommunity.microsoft.com/t5/microsoft-entra-blog/how-to-break-the-aitm-phishing-chain/ba-p/3557300
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