CVE-2018-5241 Auth bypass in Advanced Secure Gateway (ASG)

Critical 9.8 Published 29 May 2018 Updated 17 Sep 2024

Remote attackers can bypass user authentication in intercepted proxy traffic by manipulating SAML responses, affecting Symantec ASG and ProxySG.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2018-5241?

CVE-2018-5241 is a critical authentication bypass vulnerability in Symantec Corporation Advanced Secure Gateway (ASG), published on 29 May 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Symantec Advanced Secure Gateway (ASG) 6.6 and 6.7, and ProxySG 6.5, 6.6, and 6.7 are susceptible to a SAML authentication bypass vulnerability. The products can be configured with a SAML authentication realm to authenticate network users in intercepted proxy traffic. When parsing SAML responses, ASG and ProxySG incorrectly handle XML nodes with comments. A remote attacker can modify a valid SAML response without invalidating its cryptographic signature. This may allow the attacker to bypass user authentication security controls in ASG and ProxySG. This vulnerability only affects authentication of network users in intercepted traffic. It does not affect administrator user authentication for the ASG and ProxySG management consoles.

Which versions are affected by CVE-2018-5241?

It affects 2 products.

Products include Broadcom Advanced Secure Gateway, Broadcom Symantec Proxysg.

How do I fix CVE-2018-5241?

No fix has been published for CVE-2018-5241 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2018-5241 being exploited?

There is no known exploitation of CVE-2018-5241 in the wild and no public exploit code.

Sources

Also known as GHSA-vf9c-2j2h-8frq.