Pierluigi Paganini December 13, 2016

Intel Security McAfee VirusScan Enterprise for Linux is affected by ten vulnerabilities that can be chained for remote code execution with root privileges.

The security expert Andrew Fasano discovered multiple vulnerabilities in the Intel Security’s McAfee VirusScan Enterprise solution for Linux, one of them can be chained by attackers to gain root privileges and remote execute code.

Mr. Fasano reported the issues to Intel Security via CERT/CC in June, but public disclosure of the issues arrived a few days ago once the company issues necessary patches last week. The security researcher has also published proof-of-concept (PoC) code for this attack chain.

The security solution is affected by a wide range of flaws, including information disclosure, cross-site request forgery (CSRF), cross-site scripting (XSS), remote code execution, privilege escalation, special element injection, authentication brute-force, SQL injection, and arbitrary file write issues.

“A system running Intel’s McAfee VirusScan Enterprise for Linux can be compromised by remote attackers due to a number of security vulnerabilities. Some of these vulnerabilities can be chained together to allow remote code execution as root.” wrote Fasano in a blog post.

Four out of ten vulnerabilities are rated as having high severity, while the remaining issued have been rated medium severity.

Fasano explained the entire attack chain to compromise the Intel Security’s McAfee VirusScan Enterprise solution for Linux, the hack starts triggering a flaw that allows the remote use of authentication tokens (CVE-2016-8022) that have been brute-forced (CVE-2016-8023).

The attacker then deploys a malicious update server and triggers the CVE-2016-8022 to configure the product to use that server. The attacker exploits an arbitrary file write vulnerability (CVE-2016-8021) to create a malicious script obtained from the update server. The script can be executed with root privileges by exploiting the privilege escalation CVE-2016-8020.

The last step consists in sending a malformed request with authentication token to start virus scan that instead executes the malicious script with root permissions.

“To execute code as the root user on a remote machine:

1. Brute force authentication token using Vulnerability 7 and Vulnerability 8.
2. Start running malicious update server.
3. Send request with authentication token to update update server using Vulnerability 7.
4. Force target to create malicious script on their system using Vulnerability 6.
5. Send malformed request with authentication token to start virus scan but execute malicious script instead by using Vulnerability 5 and Vulnerability 6.
6. The malicious script is then run by the root user on the victim machine.

Exploiting this vulnerability depends on the existence of a valid login token which is generated whenever a user logs into the web interface. These tokens are valid for approximately an hour after login.” states Fasano.

According to Intel Security, the flaws affect VirusScan Enterprise for Linux (VSEL) 2.0.3 and earlier. The company urges users to upgrade to Endpoint Security for Linux (ENSL) 10.2 or later because the VSEL product will soon reach the end of life

The CERT/CC published a security advisor to inform customers of the flaws in the McAfee Virus Scan Enterprise.

“McAfee has discontinued the Virus Scan Enterprise product in favor of the new McAfee Endpoint Security product, which addresses these vulnerabilities. Affected users are encouraged to upgrade to Endpoint Security version 10.2 or later as soon as possible. The upgrade is available free of charge to existing users.” is the solution provided by the CERT.

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Pierluigi Paganini

(Security Affairs – McAfee VirusScan Enterprise, Linux)