Suspicious JSP Webshell Compiled Class Creation in Web Application Work Directory

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 a compiled JSP class named welcome_jsp associated with the webshell dropped during F5 and Citrix exploitation observed by NCC Group. Web application servers compile deployed JSP files into class artifacts and an unexpected welcome webshell class indicates server side code execution persistence.

Reporting behind it

Related detections9 linkedT1505.003 — drag to rearrange

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Suspicious JSP Webshell Compiled Class Creation in Web Application Work Directory

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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