CyberSecBulletin
CVE-2024-20402NVD status: Analyzed

Cisco Adaptive Security Appliance (ASA) Software: Access of Memory Location After End of Buffer

Published Updated By the CyberSecBulletin desk

CVE-2024-20402 is a high-severity access of memory location after end of buffer vulnerability in Cisco Adaptive Security Appliance (ASA) Software from Cisco, with a CVSS 3.1 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Cisco Adaptive Security Appliance (ASA) Software versions: 9.8.1; 9.8.1.5; 9.8.1.7, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.53% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Cisco Adaptive Security Appliance (ASA) Software you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
CiscoCisco Adaptive Security Appliance (ASA) Software9.8.1; 9.8.1.5; 9.8.1.7; 9.8.2; 9.8.2.8; 9.8.2.14; 9.8.2.15; 9.8.2.17; and 32 more rangesNot stated
CiscoCisco Firepower Threat Defense Software6.2.3; 6.2.3.1; 6.2.3.2; 6.2.3.3; 6.2.3.4; 6.2.3.5; 6.2.3.6; 6.2.3.7; and 32 more rangesNot stated
Ciscoadaptive_security_appliance9.8.1 through 9.8.4.48; 9.12.1 through 9.12.4.67; 9.14.1 through 9.14.4.24; 9.15.1 through 9.15.1.21; 9.16.1 through 9.16.4.61; 9.17.1 through 9.17.1.39; 9.18.1 through 9.18.4.29; 9.19.1 through 9.19.1.31Not stated
Ciscofirepower_threat_defense_software6.2.3 through 6.2.3.18; 6.4.0 through 6.4.0.18; 6.6.0 through 6.6.7.2; 6.7.0 through 6.7.0.3; 7.0.0 through 7.0.6.2; 7.1.0 through 7.1.0.3; 7.2.0 through 7.2.8.1; 7.3.0 through 7.3.1.2Not stated
CiscoAdaptive Security Appliance Software9.8.1; 9.8.1.5; 9.8.1.7; 9.8.2; 9.8.2.8; 9.8.2.14; 9.8.2.15; 9.8.2.17; and 32 more rangesNot stated
CiscoSecure Firewall Threat Defense6.2.3; 6.2.3.1; 6.2.3.2; 6.2.3.3; 6.2.3.4; 6.2.3.5; 6.2.3.6; 6.2.3.7; and 32 more rangesNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.6HighCNA (cisco.com)
CVSS 3.18.6HighNVD

Official description

A vulnerability in the SSL VPN feature for Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a logic error in memory management when the device is handling SSL VPN connections. An attacker could exploit this vulnerability by sending crafted SSL/TLS packets to the SSL VPN server of the affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Access of Memory Location After End of Buffer

The product reads or writes to a buffer using an index or pointer that references a memory location after the end of the buffer.

More Access of Memory Location After End of Buffer vulnerabilities (CWE-788)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Cisco Adaptive Security Appliance (ASA) Software

All Cisco Adaptive Security Appliance (ASA) Software vulnerabilities

Recent Access of Memory Location After End of Buffer vulnerabilities

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