Suspicious Web Shell ASPX File Created in Exchange OWA Auth or SharePoint LAYOUTS Path (via file_event)

ATT&CK techniques

Persistence

Recon
Resource Dev
Initial Access
Execution
Persistence
- T1505.003Web Shell
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects creation of web-shell ASPX files named getidtoken.aspx or signout.aspx within Exchange OWA authentication, aspnet_client, or SharePoint LAYOUTS directories, the persistence artifacts dropped in attacks against on-premises Exchange and SharePoint servers. Adversaries place shells with authentication-themed names in trusted server paths to blend in and retain access, so these files appearing in those locations indicate web-shell installation.

Reporting behind it

Related detections9 linkedT1505.003 — drag to rearrange

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Suspicious Web Shell ASPX File Created in Exchange OWA Auth or SharePoint LAYOUTS Path (via file_event)

Pivot detection · T1505.003 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

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