PHP Web Shell Jalang.php

The Jalang PHP web shell has the functionality to provide entries in the /etc/passwd file. In addition to that, it attempts to read and retrieve certain files from the webserver root directory. It checks these files for credentials and attempts to connect to FTP over localhost. Additionally, there is a mailing function to send the host header and URI to the attacker’s Gmail account. The shell could be uploaded to the server via a vulnerability or some other misconfiguration.

Exploitation

Stages

1. The attacker uploads shells to the vulnerable or misconfigured system.
2. The attacker attempts to access the Jalang web shell functionality to carry out malicious objectives.
3. The server responds indicating its presence and the result of the attacker’s request.

Prerequisites

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.