CVE-2024-33602: GNU Glibc Buffer Overflow Vulnerability

CVE-2024-33602 Overview

CVE-2024-33602 is a memory corruption vulnerability in the GNU C Library (glibc) Name Service Cache Daemon (nscd). The vulnerability exists in the netgroup cache functionality, where the cache can corrupt memory when the NSS (Name Service Switch) callback does not store all strings in the provided buffer. This flaw was introduced in glibc version 2.15 when the netgroup cache was added to nscd.

The vulnerability is specifically present in the nscd binary and affects systems that use the netgroup caching functionality. Successful exploitation could allow an attacker to corrupt memory, potentially leading to denial of service or arbitrary code execution with the privileges of the nscd daemon.

Critical Impact

Memory corruption in nscd's netgroup cache can lead to system instability, denial of service, or potential code execution on affected Linux systems running vulnerable glibc versions.

Affected Products

• GNU glibc (versions 2.15 and later)
• Debian Linux 10.0
• NetApp H300S/H500S/H700S/H410S/H410C Series (firmware and hardware)
• NetApp Element Software
• NetApp SolidFire & HCI Management Node
• NetApp SolidFire & HCI Storage Node
• NetApp HCI Bootstrap OS

Discovery Timeline

• May 6, 2024 - CVE-2024-33602 published to NVD
• June 18, 2025 - Last updated in NVD database

Technical Details for CVE-2024-33602

Vulnerability Analysis

The vulnerability stems from an incorrect assumption in the nscd netgroup cache implementation. When processing netgroup queries, the cache expects the NSS callback function to store all string data within a designated buffer. However, if the NSS callback does not properly store all strings in the provided buffer, the cache management code can operate on memory outside the intended buffer boundaries.

This memory corruption vulnerability (CWE-466: Return of Pointer Value Outside of Expected Range) occurs because the nscd daemon does not properly validate that all returned string pointers actually reference memory within the allocated cache buffer. When strings are stored outside this buffer, subsequent cache operations can corrupt adjacent memory regions.

The attack requires local access to the system, though the exploitation complexity is high due to the specific conditions required to trigger the vulnerability. An attacker would need to manipulate NSS responses in a way that causes the callback to store strings outside the expected buffer boundaries.

Root Cause

The root cause of CVE-2024-33602 lies in the design assumption made when the netgroup cache was implemented in glibc 2.15. The cache implementation assumes that NSS callback functions will always store string data within the buffer provided by nscd. This assumption fails when:

1. The NSS backend returns pointers to static or global string storage instead of copying data into the provided buffer
2. The callback function uses memory outside the designated cache buffer for string storage
3. Custom NSS modules do not adhere to the expected memory management contract

This leads to the cache operating on invalid pointer references, causing memory corruption when the cache attempts to manage or access these out-of-buffer strings.

Attack Vector

The attack vector for CVE-2024-33602 is local, requiring an attacker to have access to the target system. Exploitation involves triggering netgroup lookups through nscd that result in NSS callbacks storing strings outside the designated buffer.

The attack mechanism can be described as follows:

1. The attacker triggers a netgroup lookup request through the nscd daemon
2. The NSS callback processes the request but stores string data outside the provided buffer
3. The nscd netgroup cache stores pointers to these out-of-buffer strings
4. Subsequent cache operations using these invalid pointers corrupt memory
5. This corruption can lead to denial of service or potentially arbitrary code execution

The vulnerability requires specific conditions to exploit, including the presence of NSS backends that do not properly store strings in the provided buffer. For detailed technical analysis, refer to the glibc Advisory GLIBC-SA-2024-0008.

Detection Methods for CVE-2024-33602

Indicators of Compromise

• Unexpected crashes or segmentation faults in the nscd daemon process
• Abnormal memory usage patterns associated with nscd netgroup cache operations
• System log entries indicating nscd memory corruption or cache inconsistencies
• Core dumps from nscd showing memory access violations

Detection Strategies

• Monitor nscd process stability and restart frequency for unusual patterns
• Implement system call monitoring to detect anomalous nscd memory operations
• Use memory analysis tools to identify heap corruption in nscd processes
• Deploy endpoint detection solutions capable of identifying memory corruption exploitation attempts

Monitoring Recommendations

• Enable comprehensive logging for nscd operations and netgroup lookups
• Configure alerting for nscd daemon crashes or unexpected restarts
• Monitor system memory usage for signs of corruption or exhaustion related to nscd
• Implement process monitoring to detect unusual behavior in nscd child processes

How to Mitigate CVE-2024-33602

Immediate Actions Required

• Update glibc to the latest patched version from your distribution vendor
• Review and apply security updates from Debian, NetApp, and other affected vendors
• Consider disabling nscd netgroup caching if not required for system operation
• Audit custom NSS modules for proper buffer handling compliance

Patch Information

Organizations should apply patches provided by their operating system vendors. The following resources provide official patch information:

• glibc Advisory GLIBC-SA-2024-0008 - Official glibc security advisory
• Debian LTS Announcement - Debian security update
• NetApp Security Advisory - NetApp product updates

Workarounds

• Disable the nscd netgroup cache by setting enable-cache netgroup no in /etc/nscd.conf
• Restrict access to nscd socket to trusted users and processes only
• Consider running nscd with reduced privileges using security frameworks like SELinux or AppArmor
• Monitor nscd operations closely until patches can be applied

# Disable nscd netgroup cache as a temporary workaround
# Edit /etc/nscd.conf and add or modify the following line:
enable-cache netgroup no

# Restart nscd to apply the configuration change
systemctl restart nscd