CVE-2024-26462: MIT Kerberos 5 Memory Leak Vulnerability

CVE-2024-26462 Overview

CVE-2024-26462 is a memory leak vulnerability discovered in MIT Kerberos 5 (krb5) version 1.21.2. The flaw exists within the /krb5/src/kdc/ndr.c file, which is responsible for Network Data Representation (NDR) processing in the Key Distribution Center (KDC). When exploited, this vulnerability allows a local authenticated attacker to cause resource exhaustion through repeated memory allocation without proper deallocation, potentially leading to denial of service conditions on the affected system.

Critical Impact

Memory leak in the KDC component can lead to gradual resource exhaustion, causing denial of service for Kerberos authentication services across the enterprise environment.

Affected Products

• MIT Kerberos 5 version 1.21.2
• NetApp Active IQ Unified Manager for VMware vSphere
• NetApp Cloud Volumes ONTAP Mediator
• NetApp Management Services for Element Software and NetApp HCI
• NetApp ONTAP Select Deploy Administration Utility
• NetApp H610C, H610S, and H615C (hardware and firmware)

Discovery Timeline

• 2024-02-29 - CVE-2024-26462 published to NVD
• 2024-04-15 - NetApp releases security advisory NTAP-20240415-0012
• 2025-03-25 - Last updated in NVD database

Technical Details for CVE-2024-26462

Vulnerability Analysis

This memory leak vulnerability (CWE-401: Missing Release of Memory after Effective Lifetime) occurs in the NDR processing code within the Kerberos Key Distribution Center. The affected code path fails to properly release allocated memory under certain conditions during NDR data handling operations.

Memory leaks in long-running services like the KDC are particularly impactful because the service typically runs continuously to handle authentication requests. Each leaked memory allocation accumulates over time, eventually consuming all available system memory and causing the KDC service to become unresponsive or crash.

The vulnerability requires local access and low privileges to exploit, meaning an attacker would need some level of authenticated access to the target system to trigger the vulnerable code path repeatedly.

Root Cause

The root cause of this vulnerability lies in improper memory management within the ndr.c source file. The code allocates memory during NDR processing operations but fails to include corresponding deallocation routines for certain execution paths. This results in orphaned memory blocks that cannot be reclaimed by the system until the process terminates.

The vulnerability is classified as CWE-401 (Missing Release of Memory after Effective Lifetime), indicating that dynamically allocated memory is not freed after it is no longer needed, which allows attackers to exhaust available memory resources through repeated triggering of the vulnerable function.

Attack Vector

The attack vector for CVE-2024-26462 is local, requiring the attacker to have authenticated access to a system running the vulnerable KDC. The attacker can exploit this vulnerability by:

1. Sending specially crafted requests to the KDC that trigger the vulnerable NDR processing code
2. Repeating these requests to cause cumulative memory allocation without deallocation
3. Continuing until the system's available memory is exhausted, causing denial of service

The vulnerability mechanism involves improper memory handling in the NDR processing functions. When specific data structures are processed, the allocated memory is not properly tracked for cleanup, leading to persistent memory consumption. Technical analysis of this defect is available in the GitHub krb5 Defect Analysis.

Detection Methods for CVE-2024-26462

Indicators of Compromise

• Abnormally high memory consumption by the krb5kdc process over time
• Gradual increase in resident memory size without corresponding decrease during idle periods
• System memory exhaustion alerts on servers running KDC services
• KDC service crashes or restarts due to out-of-memory conditions

Detection Strategies

• Monitor the memory footprint of KDC processes using system monitoring tools and alert on continuous growth patterns
• Implement memory profiling on KDC servers to identify memory allocation trends
• Review KDC service logs for crash reports or out-of-memory errors
• Use SentinelOne Singularity platform to detect anomalous process behavior and resource consumption patterns

Monitoring Recommendations

• Configure memory usage thresholds for KDC processes with alerting when exceeded
• Implement trend analysis for memory consumption to detect gradual increases over time
• Monitor system-level memory availability on all authentication infrastructure
• Deploy endpoint detection and response (EDR) solutions to track process behavior anomalies

How to Mitigate CVE-2024-26462

Immediate Actions Required

• Identify all systems running MIT Kerberos 5 version 1.21.2 and affected NetApp products in your environment
• Apply vendor patches as they become available from MIT and NetApp
• Implement memory monitoring for KDC processes to detect exploitation attempts
• Consider implementing service restart schedules as a temporary measure to reclaim leaked memory

Patch Information

Organizations should consult the official vendor advisories for patch availability:

• Review the NetApp Security Advisory NTAP-20240415-0012 for guidance on affected NetApp products
• Monitor MIT Kerberos release announcements for updated versions addressing this vulnerability
• Consult the GitHub krb5 Defect Analysis for technical details on the affected code

Workarounds

• Implement scheduled restarts of KDC services during maintenance windows to reclaim leaked memory
• Deploy additional KDC replicas to distribute load and provide redundancy if a KDC becomes unresponsive
• Implement resource limits (cgroups/ulimits) on KDC processes to prevent complete system memory exhaustion
• Monitor and alert on memory consumption thresholds to enable proactive intervention

# Example: Configure memory monitoring for krb5kdc process
# Add to crontab for periodic memory checking
*/5 * * * * /usr/bin/pgrep -f krb5kdc | xargs ps -o pid,rss,vsz --no-headers >> /var/log/kdc_memory.log

# Example: Set memory limits for KDC service (systemd)
# Add to /etc/systemd/system/krb5kdc.service.d/limits.conf
# [Service]
# MemoryMax=2G
# MemoryHigh=1.5G