QID 317060

Date Published: 2021-09-29

QID 317060: Cisco Internetwork Operating System (IOS) XE Software H.323 Application Level Gateway Bypass Vulnerability (cisco-sa-iosxe-h323alg-bypass-4vy2MP2Q)

A vulnerability in the H.323 application level gateway (ALG) used by the Network Address Translation (NAT) feature
of Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass the ALG.

Affected Products
Cisco devices if they were running a vulnerable release of Cisco IOS XE Software, were configured for NAT, and
had the H.323 ALG enabled. The H.323 ALG is enabled by default when NAT is configured.

QID Detection Logic (Authenticated):
The check matches Cisco IOS XE version retrieved via Unix Auth using "show version" command.
QID Detection Logic (Unauthenticated):
The check matches Cisco IOS XE version retrieved via SNMP or TCP/IP Fingerprint or NTP or Telnet.

A successful exploit could allow the attacker to bypass the ALG and open connections that should not be allowed to a remote device located behind the ALG.

  • CVSS V3 rated as Medium - 4.7 severity.
  • CVSS V2 rated as Medium - 4.3 severity.
    • Solution

    Customers are advised to refer to cisco-sa-iosxe-h323alg-bypass-4vy2MP2Q for more information.

    Vendor References

    CVEs related to QID 317060

    CVE-2021-1616 |
    Software Advisories
    Advisory ID Software Component Link
    cisco-sa-iosxe-h323alg-bypass-4vy2MP2Q URL Logo tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-h323alg-bypass-4vy2MP2Q
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