↳ GitHub sourceAnalytics ruleMedium
Exchange Server Suspicious File Downloads.
Description
'This query looks for messages related to file downloads of suspicious file types on an Exchange Server. This could indicate attempted deployment of webshells.
This query uses the Exchange HttpProxy AOBGeneratorLog, you will need to onboard this log as a custom log under the table http_proxy_oab_CL before using this query.
This log is commonly found at C:\Program Files\Microsoft\Exchange Server\V15\Logging\OABGeneratorLog on the Exchange server. Details on collecting custom logs into Sentinel
can be found here: https://learn.microsoft.com/en-us/azure/sentinel/connect-custom-logs-ama'
- Rule type
- Scheduled
- Version
- 1.0.5
- Query frequency
- 1d
- Query period
- 1d
- Trigger
- gt 0
Declared MITRE coverage
KQL query
Original query, unchanged.
let scriptExtensions = dynamic([".php", ".jsp", ".js", ".aspx", ".asmx", ".asax", ".cfm", ".shtml"]);
http_proxy_oab_CL
| where RawData contains "Download failed and temporary file"
| extend File = extract("([^\\\\]*)(\\\\[^']*)",2,RawData)
| extend Extension = strcat(".",split(File, ".")[-1])
| extend InteractiveFile = iif(Extension in (scriptExtensions), "Yes", "No")
// Uncomment the following line to alert only on interactive file download type
//| where InteractiveFile =~ "Yes"
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
Declared entities
Source provenance
GitHubDisplayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.
- Commit
629d1d3↗- Source identifier
8955c0fb-3408-47b0-a3b9-a1faec41e427
Additional source files 1
Detections/http_proxy_oab_CL/ExchagngeSuspiciousFileDownloads.yamlsource ↗GSTEP / CATALOG TRACKING
Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC