CVE-2024-41184: Keepalived DOS Vulnerability

CVE-2024-41184 Overview

CVE-2024-41184 is an integer overflow vulnerability discovered in the vrrp_ipsets_handler handler within the fglobal_parser.c file of Keepalived through version 2.3.1. This vulnerability allows for potential memory corruption through integer overflow conditions when processing ipset configurations. While the vulnerability has a high severity rating, it requires specific user configuration (an empty ipset name) to be exploitable, which may limit its practical attack surface.

Critical Impact

An integer overflow in Keepalived's VRRP ipsets handler could potentially lead to memory corruption, allowing attackers with network access to compromise high-availability infrastructure components with full impact to confidentiality, integrity, and availability.

Affected Products

• Keepalived through version 2.3.1
• Systems utilizing VRRP (Virtual Router Redundancy Protocol) with ipset configurations
• High-availability Linux deployments using Keepalived for failover management

Discovery Timeline

• 2024-07-18 - CVE CVE-2024-41184 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-41184

Vulnerability Analysis

This vulnerability is classified as CWE-190 (Integer Overflow or Wraparound). The flaw exists in the vrrp_ipsets_handler function within fglobal_parser.c, where improper handling of integer calculations can result in an overflow condition. When triggered, the integer overflow can cause unexpected behavior in memory allocation or buffer operations, potentially leading to memory corruption.

The vulnerability requires network-level access and can be exploited without authentication or user interaction. However, the practical exploitability is somewhat limited by the prerequisite that an empty ipset name must be configured by the user—a non-default and unusual configuration choice.

Root Cause

The root cause stems from insufficient validation of integer values within the vrrp_ipsets_handler function. When processing ipset configuration parameters, the code fails to properly check for potential overflow conditions before performing arithmetic operations. This CWE-190 weakness allows calculated values to wrap around, potentially resulting in undersized buffer allocations or incorrect boundary checks.

Attack Vector

The attack vector is network-based, requiring an attacker to send specially crafted requests that trigger the integer overflow condition in the VRRP ipsets handler. The exploitation path involves:

1. Identifying a Keepalived instance with an empty ipset name configured
2. Crafting malicious input that causes integer overflow during handler processing
3. Leveraging the resulting memory corruption to potentially achieve code execution or denial of service

Since no proof-of-concept code has been verified for this vulnerability, technical details about specific exploitation techniques should be obtained from the GitHub Issue discussing this vulnerability.

Detection Methods for CVE-2024-41184

Indicators of Compromise

• Unexpected crashes or restarts of the Keepalived daemon
• Anomalous memory consumption patterns in Keepalived processes
• Core dumps indicating memory corruption in fglobal_parser.c or related VRRP components
• Unusual network traffic patterns targeting Keepalived services

Detection Strategies

• Monitor Keepalived process stability and implement alerting for unexpected daemon terminations
• Deploy memory corruption detection tools (AddressSanitizer, Valgrind) in staging environments to identify exploitation attempts
• Implement network intrusion detection rules for anomalous VRRP traffic patterns
• Audit Keepalived configurations to identify instances with empty ipset names

Monitoring Recommendations

• Enable verbose logging for Keepalived to capture detailed handler execution information
• Implement process monitoring to detect crashes or abnormal behavior in Keepalived instances
• Configure system-level crash reporting to capture and analyze core dumps from Keepalived
• Monitor network traffic on VRRP-related ports for unusual patterns or volumes

How to Mitigate CVE-2024-41184

Immediate Actions Required

• Audit all Keepalived configurations and remove or populate any empty ipset name entries
• Update Keepalived to the latest available version that addresses this vulnerability
• Implement network segmentation to limit access to Keepalived instances from untrusted networks
• Consider deploying application-level firewalls to filter malicious requests to VRRP services

Patch Information

Organizations should monitor the official Keepalived repository and release channels for security patches addressing CVE-2024-41184. The vulnerability was identified through GitHub Issue #2447, which may contain additional remediation guidance from the maintainers.

Workarounds

• Ensure no empty ipset names are configured in Keepalived configuration files
• Restrict network access to Keepalived services using firewall rules to trusted management networks only
• Implement additional input validation at the network perimeter for VRRP-related traffic
• Consider deploying Keepalived in isolated network segments with strict access controls

# Configuration example - Ensure ipset names are not empty
# Review your keepalived.conf for any empty ipset declarations
grep -r "ipset" /etc/keepalived/
# Verify all ipset entries have valid, non-empty names
# Example of a properly configured ipset (not empty):
# ipset my_ipset_name