CVE-2024-26458: MIT Kerberos 5 Information Disclosure

CVE-2024-26458 Overview

CVE-2024-26458 is a memory leak vulnerability discovered in MIT Kerberos 5 (krb5) version 1.21.2. The vulnerability exists within the /krb5/src/lib/rpc/pmap_rmt.c file, where improper memory management leads to memory not being properly released after allocation. This flaw can be exploited remotely over the network without requiring authentication or user interaction.

Critical Impact

Sustained exploitation of this memory leak vulnerability could lead to resource exhaustion and potential denial of service conditions on systems running vulnerable versions of MIT Kerberos 5.

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 9
• NetApp ONTAP Select Deploy Administration Utility
• NetApp H610C/H610S/H615C firmware and hardware

Discovery Timeline

• 2024-02-29 - CVE-2024-26458 published to NVD
• 2025-05-23 - Last updated in NVD database

Technical Details for CVE-2024-26458

Vulnerability Analysis

This vulnerability is classified as CWE-401 (Missing Release of Memory after Effective Lifetime), a common memory management flaw where allocated memory is not properly deallocated when no longer needed. In the context of the Kerberos 5 RPC library, the pmap_rmt.c file handles portmapper remote procedure calls, and the memory leak occurs during these operations.

The vulnerability can be triggered remotely over the network. An attacker does not need any special privileges or user interaction to exploit this flaw. While the immediate impact is limited to information disclosure with low confidentiality impact, repeated exploitation could cause memory exhaustion leading to service degradation or denial of service.

The flaw is particularly concerning in enterprise environments where Kerberos authentication is critical for infrastructure security, as the affected component handles RPC communications for the portmapper service.

Root Cause

The root cause of CVE-2024-26458 is improper memory management in the pmap_rmt.c source file within the krb5 RPC library. Specifically, memory allocated during portmapper remote procedure call operations is not properly released after use, leading to progressive memory consumption over time. This represents a classic memory leak pattern where the code path responsible for freeing allocated resources fails to execute under certain conditions.

Attack Vector

The attack vector for this vulnerability is network-based. An attacker can trigger the memory leak by sending specially crafted requests that cause the vulnerable code path in pmap_rmt.c to execute without properly releasing allocated memory. The attack requires:

• Network access to a vulnerable Kerberos 5 service
• No authentication or special privileges
• No user interaction

The vulnerability is documented in the GitHub PoC Repository which provides technical details about the memory leak condition. The attack complexity is low, making it relatively straightforward to exploit once network access is established.

Detection Methods for CVE-2024-26458

Indicators of Compromise

• Abnormal memory consumption patterns on systems running Kerberos 5 services
• Gradual increase in memory usage for KDC (Key Distribution Center) processes without corresponding increase in legitimate traffic
• Process memory footprint growing continuously over time without release
• System logs indicating memory allocation failures or out-of-memory conditions

Detection Strategies

• Monitor memory usage trends for Kerberos-related processes (krb5kdc, kadmind) using system monitoring tools
• Implement memory usage thresholds and alerts for critical authentication services
• Review system resource utilization logs for anomalous patterns indicating potential exploitation attempts
• Deploy intrusion detection rules to identify suspicious RPC traffic patterns targeting Kerberos services

Monitoring Recommendations

• Configure continuous memory monitoring for all systems running MIT Kerberos 5 version 1.21.2 or affected NetApp products
• Establish baseline memory consumption metrics and alert on deviations exceeding normal operational parameters
• Implement log aggregation for Kerberos service events to correlate potential exploitation attempts
• Schedule periodic service restarts as a temporary measure to reclaim leaked memory until patches are applied

How to Mitigate CVE-2024-26458

Immediate Actions Required

• Identify all systems running MIT Kerberos 5 version 1.21.2 and affected NetApp products in your environment
• Review the NetApp Security Advisory for vendor-specific guidance
• Implement network segmentation to limit exposure of Kerberos services to trusted networks only
• Monitor affected systems for memory exhaustion conditions and plan for service restarts if necessary

Patch Information

Organizations should monitor vendor channels for security updates addressing this vulnerability. The NetApp Security Advisory provides specific information for NetApp products. For MIT Kerberos 5, check the official MIT Kerberos distribution channels for patched versions addressing the memory leak in pmap_rmt.c.

Ensure all affected products including NetApp Active IQ Unified Manager, Cloud Volumes ONTAP Mediator, Management Services for Element Software, ONTAP 9, ONTAP Select Deploy Administration Utility, and H-series firmware are updated according to vendor recommendations.

Workarounds

• Restrict network access to Kerberos services using firewall rules to minimize exposure to untrusted networks
• Implement scheduled service restarts during maintenance windows to reclaim leaked memory
• Deploy resource limits (ulimit, cgroups) for Kerberos processes to prevent complete system memory exhaustion
• Consider implementing reverse proxy or load balancer rate limiting to reduce the frequency of triggerable requests

# Configuration example
# Implement memory monitoring for Kerberos processes
# Add to cron for periodic memory checks
cat >> /etc/cron.d/krb5-memory-monitor << 'EOF'
*/15 * * * * root /usr/bin/pmap $(pgrep krb5kdc) | tail -1 >> /var/log/krb5-memory.log
EOF

# Set memory limits for Kerberos services
# Add to systemd service override
mkdir -p /etc/systemd/system/krb5-kdc.service.d
cat > /etc/systemd/system/krb5-kdc.service.d/memory-limit.conf << 'EOF'
[Service]
MemoryLimit=2G
EOF
systemctl daemon-reload