CVE intelligence and bounded remediation

CVE-2018-5241 — Broadcom Advanced Secure Gateway security vulnerability

Critical CVSS 9.8

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.

Severity
Critical
CVSS
9.8 (3.0)
Published
2018-05-29
CISA KEV
Not currently listed
Ecosystem
software/application

Affected products

  • broadcom / advanced_secure_gateway / 6.6
  • broadcom / advanced_secure_gateway / 6.7
  • broadcom / symantec_proxysg / 6.5
  • broadcom / symantec_proxysg / 6.6
  • broadcom / symantec_proxysg / 6.7

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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