↳ GitHub sourceAnalytics ruleMedium
Silk Typhoon Suspicious Exchange Request
Description
'This query looks for suspicious request patterns to Exchange servers that fit a pattern observed by Silk Typhoon actors.
The same query can be run on HTTPProxy logs from on-premise hosted Exchange servers.
Reference: https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/'
- Rule type
- Scheduled
- Version
- 1.0.3
- Query frequency
- 1d
- Query period
- 14d
- Trigger
- gt 0
Declared MITRE coverage
Declared sources
Metadata from the source file. No dependencies inferred from KQL.
Connectors
Data types
KQL query
Original query, unchanged.
let exchange_servers = (
W3CIISLog
| where TimeGenerated > ago(14d)
| where sSiteName =~ "Exchange Back End"
| summarize by Computer);
W3CIISLog
| where TimeGenerated > ago(1d)
| where Computer in (exchange_servers)
| where csUriQuery startswith "t="
| project-reorder TimeGenerated, Computer, csUriStem, csUriQuery, csUserName, csUserAgent, cIP
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(csUserName, "@")[0]), AccountUPNSuffix = tostring(split(csUserName, "@")[1])
Declared entities
Source provenance
GitHubDisplayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.
- Commit
9800e51↗- Source identifier
23005e87-2d3a-482b-b03d-edbebd1ae151
Additional source files 1
Detections/W3CIISLog/SilkTyphoonSuspiciousExchangeRequestPattern.yamlsource ↗GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC