There are two staging shells with the functionality to evaluate PHP code and upload files to the web server directory in which the web shell resides. These shells can be uploaded to a webserver via a vulnerability or misconfigured upload mechanism. This tactic is usually utilized as a precursor to uploading further files that could lead to a compromise of the system.
- An attacker uploads a PHP web shell to the vulnerable server via an upload mechanism or vulnerability.
- The server responds indicating a successful upload.
- The attacker acts upon objectives by utilizing the shell’s functionality.
The attacker must be able to inject the malicious code onto the web server through another vulnerability or exploit.
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
The attacker must have exploited some other entry vector to allow the malicious files to become resident on the victim machine.