CyberSecBulletin
CVE-2024-20271NVD status: Analyzed

A vulnerability in the IP packet processing of Cisco Access Point (AP) Software could allow an…

Published Updated By the CyberSecBulletin desk

CVE-2024-20271 is a high-severity improper input validation vulnerability in Cisco Aironet Access Point 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 Aironet Access Point Software versions: 8.2.100.0; 8.2.130.0; 8.2.111.0, 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 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update iOS Xe to 17.3.8 or 17.6.6 or 17.9.5 or 17.12.2, whichever matches your release line, or a later version.
  2. Update Business Access Points to 10.9.1.0 or 10.6.2.0, whichever matches your release line, or a later version.
  3. Update Wireless Lan Controller Software to 8.10.190.0 or a later version.
  4. Read the advisory on sec.cloudapps.cisco.com for workarounds and exact fixed builds.
  5. 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 Aironet Access Point Software8.2.100.0; 8.2.130.0; 8.2.111.0; 8.2.110.0; 8.2.121.0; 8.2.141.0; 8.2.151.0; 8.2.160.0; and 32 more rangesNot stated
CiscoCisco Business Wireless Access Point Software10.0.1.0; 10.0.2.0; 10.1.1.0; 10.1.2.0; 10.2.1.0; 10.2.2.0; 10.3.1.0; 10.3.1.1; and 32 more rangesNot stated
CiscoCisco Aironet Access Point Software (IOS XE Controller)16.10.1e; 16.10.1; 17.1.1t; 17.1.1s; 17.1.1; 16.11.1a; 16.11.1; 16.11.1c; and 32 more rangesNot stated
Ciscoaironet_access_point_software8.10.111.0; 8.10.112.0; 8.10.113.0; 8.10.121.0; 8.10.122.0; 8.10.130.0; 8.10.141.0; 8.10.142.0; and 32 more rangesNot stated
CiscoiOS Xebefore 17.3.8; 17.4 up to, but not including, 17.6.6; 17.7 up to, but not including, 17.9.5; 17.10 up to, but not including, 17.12.217.3.8, 17.6.6, 17.9.5, 17.12.2
CiscoBusiness Access Pointsbefore 10.9.1.0; before 10.6.2.010.9.1.0, 10.6.2.0
CiscoWireless Lan Controller Softwarebefore 8.10.190.08.10.190.0

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 IP packet processing of Cisco Access Point (AP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient input validation of certain IPv4 packets. An attacker could exploit this vulnerability by sending a crafted IPv4 packet either to or through an affected device. A successful exploit could allow the attacker to cause an affected device to reload unexpectedly, resulting in a DoS condition. To successfully exploit this vulnerability, the attacker does not need to be associated with the affected AP. This vulnerability cannot be exploited by sending IPv6 packets.

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

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

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 Aironet Access Point Software

All Cisco Aironet Access Point Software vulnerabilities

Recent Improper Input Validation vulnerabilities

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