CyberSecBulletin
CVE-2024-3661NVD status: Analyzed

DHCP: Missing Authentication for Critical Functionality

Published Updated By the CyberSecBulletin desk

CVE-2024-3661 is a high-severity missing authentication for critical functionality vulnerability in DHCP from IETF, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected DHCP versions: 0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 4.06% chance of exploitation within 30 days, which is in the top 9.17% of all scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Forticlient to 7.2.5 or a later version.
  2. Update Secure Access Client to 24.06.1 or 24.8.5, whichever matches your release line, or a later version.
  3. Update Client Connector to 1.5.1.25 or 4.2.0.282 or 3.7.0.134, whichever matches your release line, or a later version.
  4. Read the advisory on bst.cisco.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
IETFDHCP0Not stated
FortinetForticlient6.4.0 up to, but not including, 7.2.5; 7.4.07.2.5
CiscoAnyconnect VPN ClientNot specified in the recordNot stated
CiscoSecure ClientNot specified in the recordNot stated
Palo Alto NetworksGlobalprotectNot specified in the recordNot stated
CitrixSecure Access Clientbefore 24.06.1; before 24.8.524.06.1, 24.8.5
F5Big-ip Access Policy Manager7.2.3 through 7.2.5; 15.1.0 through 15.1.10; 16.1.0 through 16.1.5; 17.1.0 through 17.1.2Not stated
WatchGuardIpsec Mobile VPN ClientNot specified in the recordNot stated
WatchGuardMobile VPN With SSLNot specified in the recordNot stated
ZscalerClient Connectorbefore 1.5.1.25; before 4.2.0.282; 3.7 up to, but not including, 3.7.0.1341.5.1.25, 4.2.0.282, 3.7.0.134

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
AdjacentThe attacker must be on the same local network segment.
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
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
LowLimited modification of data is possible.
Availability
LowPerformance or availability is reduced.

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

Scoring systemScoreSeverityScored by
CVSS 3.17.6HighCNA
CVSS 3.17.6HighNVD

Official description

DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN.

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

The underlying weakness: Missing Authentication for Critical Functionality

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

How developers prevent this class of flaw

  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
  • When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.

More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Missing Authentication for Critical Functionality vulnerabilities

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