CVE-2017-6316 Explained : Impact and Mitigation

Citrix NetScaler SD-WAN devices up to version 9.1.2.26.561201 are vulnerable to remote attackers executing unauthorized shell commands with root privileges using a specially crafted CGISESSID cookie.

Understanding CVE-2017-6316

Remote attackers can exploit a security vulnerability in Citrix NetScaler SD-WAN devices to execute unauthorized shell commands with root privileges.

What is CVE-2017-6316?

Attackers can leverage a specially crafted CGISESSID cookie to execute unauthorized shell commands with root privileges on vulnerable Citrix NetScaler SD-WAN devices.
The vulnerability affects devices up to version 9.1.2.26.561201.
Notably, on CloudBridge devices (the previous name of NetScaler SD-WAN), the cookie name was CAKEPHP instead of CGISESSID.

The Impact of CVE-2017-6316

Remote attackers can gain unauthorized access and execute commands with root privileges on vulnerable Citrix NetScaler SD-WAN devices.

Technical Details of CVE-2017-6316

Citrix NetScaler SD-WAN devices are susceptible to unauthorized command execution due to a security flaw in the handling of CGISESSID cookies.

Vulnerability Description

The vulnerability allows attackers to execute arbitrary shell commands as root by manipulating the CGISESSID cookie.

Affected Systems and Versions

Citrix NetScaler SD-WAN devices up to version 9.1.2.26.561201 are impacted by this vulnerability.

Exploitation Mechanism

Attackers exploit the vulnerability by crafting a malicious CGISESSID cookie to execute unauthorized shell commands with root privileges.

Mitigation and Prevention

Immediate Steps to Take

Disable or restrict access to potentially vulnerable services on affected devices.
Monitor network traffic for any suspicious activity related to unauthorized command execution. Long-Term Security Practices
Regularly update and patch Citrix NetScaler SD-WAN devices to mitigate known vulnerabilities.
Implement network segmentation and access controls to limit the attack surface.
Conduct security assessments and penetration testing to identify and address potential security weaknesses.
Educate users and administrators about safe browsing practices and the risks of executing unauthorized commands.
Stay informed about security advisories and updates from Citrix to proactively address emerging threats.
Collaborate with security professionals and vendors to enhance the overall security posture of the network.
Consider implementing additional security measures such as intrusion detection/prevention systems and security information and event management solutions.

Patching and Updates

Apply patches and updates provided by Citrix to address the vulnerability and enhance the security of NetScaler SD-WAN devices.