JSP Web Shell Cat

Cat is a JSP web shell that hides much of the functionality behind what is a typical web server directory listing HTML interface. Cat was seen used in a campaign against WebLogic servers vulnerable to CVE-2018-2894.

Exploitation

Stages

1. The attacker sends an HTTP request to create a reverse shell from the server.
2. Alternatively, an attacker may send an HTTP request to download the file onto the server.
3. Alternatively, an attacker may send an HTTP request to execute shell commands on the server.
4. Alternatively, an attacker may send an HTTP request to read and output the contents of a file located on the server.
5. Alternatively, an attacker may send an HTTP request to download a file from the server.
6. Alternatively, an attacker may send an HTTP request to write data to a file located on the server.
7. The server replies with an HTTP 200 OK response and a message indicating that the server was successfully compromised.

Prerequisites

The attacker must be able to send crafted packets to the target system.

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.