JSP Web Shell xjexws

Xjexws is a modified Jexboss JSP web shell used in campaigns targeting Java deserialization vulnerabilities. The web shell includes additions such as accepting commands from an HTTP header and reverse shell functionality. 

Exploitation 

Stages 

1. The attacker sends an HTTP request to the web shell on the compromised server. 
2. The compromised server replies with a 200 OK and a message indicating that the web shell is present. 

Prerequisites 

The attacker must have exploited some other entry vector to allow the malicious files to become resident on the victim machine.  

Alert Logic Coverage 

Alert Logic® has evaluated its customer base for exposure to the exploit and has developed signatures for mitigating the threat depending on the security service in place.  

The Network-Based Intrusion Detection System (IDS) has been updated with the new signatures for this exploit when detected via Alert Logic Threat Manager™. If this signature is detected, an incident is generated in the Alert Logic console.  

Recommendations for Mitigation 

Ensure that all public internet-facing hosts have available patches applied and are sufficiently hardened for public access.