PT-2021-4887 · Cisco · Cisco Asa+1

Published 2021-10-27 · Updated 2023-08-16 · CVE-2021-34790

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Name of the Vulnerable Software and Affected Versions Cisco Adaptive Security Appliance (ASA) Software (affected versions not specified) Cisco Firepower Threat Defense (FTD) Software (affected versions not specified)

Description Multiple vulnerabilities in the Application Level Gateway (ALG) for the Network Address Translation (NAT) feature could allow an unauthenticated, remote attacker to bypass the ALG and open unauthorized connections with a host located behind the ALG. The vulnerabilities are related to the incorrect implementation of security checks for standard elements in the Session Initiation Protocol (SIP) and the ALG function. These vulnerabilities have been publicly discussed as NAT Slipstreaming.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Improperly Implemented Security Check for Standard

RCE

Weakness Enumeration

CWE-358

CWE-20

Related Identifiers

BDU:2021-05622

CVE-2021-34790

Affected Products

Cisco Asa

Cisco Ftd

References · 9

• https://bdu.fstec.ru/vul/2021-05622 · Security Note
• https://osv.dev/vulnerability/CVE-2021-34790 · Vendor Advisory
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-natalg-bypass-cpKGqkng · Vendor Advisory
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-natalg-bypass-cpKGqkng · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-34790 · Security Note
• https://t.me/cibsecurity/31308 · Telegram Post
• https://t.me/cvenotify/22521 · Telegram Post
• https://cybersecurity-help.cz/vdb/SB2021102916 · Note
• https://t.me/cvenotify/22644 · Telegram Post