Google Workspace User Login with Unusual ASN
Detects the first time a Google Workspace user successfully signs in from a given source ASN within a 14-day historical window. Most users have a stable set of egress ASNs (home ISP, corporate VPN, mobile carrier). A…
Description
Detects the first time a Google Workspace user successfully signs in from a given source ASN within a 14-day historical window. Most users have a stable set of egress ASNs (home ISP, corporate VPN, mobile carrier). A new ASN for a user is a meaningful anomaly as it surfaces ISP changes and travel, but also catches AiTM phishing-kit relays whose egress ASN was never previously associated with the user.
Detection logic
Its licence does not clear it for publishing here
Sunturai publishes a detection's own text where the licence it arrived under has been reviewed and permits it, and Elastic License 2.0 has not. The query as its source wrote it, its canonical form and the hash that pins this revision are in the workspace record.
Detection requirements
- Platform
- ContainersESXiIaaSIdentity ProviderLinuxmacOSNetwork DevicesOffice SuiteSaaSWindows
The rule states no platform. This is derived from the 3 ATT&CK techniques it maps to.
- Log source category
- event_index
Known benign triggers
- Carrier-grade NAT or load-balanced corporate egress that occasionally routes through alternate ASNs.
- Legitimate first-time use of a new network: ISP change, new VPN provider, travel to a region using a different mobile carrier, new home office.
MITRE ATT&CK mappings
0 exclusive techniques.This is coverage no other published rule has; it is not this rule's total technique count.
References
| Reference | Cited by |
|---|---|
| any.run/malware-trends/tycoon/ | 12 |
| www.elastic.co/security-labs/google-workspace-attack-surface-part-one | 28 |
From the source
- At source
- Open at source
- Upstream identifier
- 1f489c86-d9c4-40de-9316-931721ca9b45
- Tagged by the source as
- Data Source: Google WorkspaceData Source: Google Workspace Audit LogsData Source: Google Workspace User Log EventsDomain: CloudDomain: IdentityDomain: SaaSNoise: HighPerformance: NormalPlatform: Google WorkspaceProfile: AggressiveResources: Investigation GuideRule Type: New TermsTactic: Credential AccessTactic: Initial AccessUse Case: Identity and Access AuditUse Case: Threat Detection
Licence
- Published under
- Elastic License 2.0Read the licence
- Attribution
- Required
Authorship
- Written by
- Published
- Sep 20, 2026
- Version
- 3