Authentication bypass in Symantec ASG and ProxySG

1) Authentication bypass

EUVDB-ID: #VU13067

Risk: Low

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:U/RL:U/RC:C]

CVE-ID: CVE-2018-5241

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker can bypass authentication on the target system.

The weakness exists due to improper processing of SAML responses that contain XML nodes with comments. A remote attacker can  modify a valid SAML response so that the target system will still validate the cryptographic signature and bypass SAML authentication security controls.

Mitigation

Cybersecurity Help is currently unaware of any solutions addressing the vulnerability.

Vulnerable software versions

Advanced Secure Gateway: 6.6 - 6.7

ProxySG: 6.5 - 6.7

External links

http://www.symantec.com/security-center/network-protection-security-advisories/SA167

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.