CVE-2022-23218: GNU Glibc Buffer Overflow Vulnerability

CVE-2022-23218 Overview

CVE-2022-23218 is a buffer overflow vulnerability in the deprecated compatibility function svcunix_create within the sunrpc module of the GNU C Library (glibc) through version 2.34. The function copies its path argument onto the stack without validating its length, which can lead to a stack-based buffer overflow. This vulnerability may result in a denial of service condition or, in cases where the application is not built with stack protector mitigations enabled, arbitrary code execution.

Critical Impact

This vulnerability allows remote attackers to potentially achieve arbitrary code execution or cause denial of service on systems running affected versions of glibc without stack protection mechanisms.

Affected Products

• GNU glibc (through version 2.34)
• Oracle Communications Cloud Native Core Unified Data Repository 22.2.0
• Oracle Enterprise Operations Monitor (versions 4.3, 4.4, 5.0)
• Debian Linux 10.0

Discovery Timeline

• January 14, 2022 - CVE-2022-23218 published to NVD
• May 5, 2025 - Last updated in NVD database

Technical Details for CVE-2022-23218

Vulnerability Analysis

The vulnerability exists in the svcunix_create function, a deprecated compatibility function used in the Sun RPC (Remote Procedure Call) implementation within glibc. This function is designed to create a Unix domain socket-based RPC service transport. The core issue stems from improper handling of the path argument that specifies the socket file path.

When processing the path argument, the function copies the input directly onto the stack without first validating the length of the string. If an attacker provides a path that exceeds the expected buffer size, this results in a classic stack-based buffer overflow condition. The consequences of exploitation depend on the target system's security posture—specifically whether stack protection mechanisms such as stack canaries are enabled during compilation.

Root Cause

The root cause is classified as CWE-120 (Buffer Copy without Checking Size of Input). The svcunix_create function lacks proper bounds checking when copying the path argument to a stack-allocated buffer. This is a fundamental input validation failure where the function implicitly trusts the length of user-supplied data without verification.

The vulnerability is particularly concerning because:

• The function operates within a core system library (glibc) that is ubiquitous in Linux environments
• RPC services may be exposed to network-accessible interfaces
• The deprecated nature of the function means it may not receive the same security scrutiny as actively maintained code

Attack Vector

The vulnerability can be exploited remotely over the network. An attacker would need to interact with an application that uses the vulnerable svcunix_create function and accepts path input that can be influenced by external sources.

The exploitation mechanism involves supplying an oversized path argument to trigger the buffer overflow. Without stack protection, this allows the attacker to overwrite the return address on the stack, redirecting execution flow to attacker-controlled code. With stack protectors enabled, exploitation typically results in a denial of service through application crash when the stack canary is corrupted.

The vulnerability mechanism operates as follows: when svcunix_create is called with a path argument, it allocates a fixed-size buffer on the stack and copies the path using an unbounded copy operation. An attacker-controlled path exceeding this buffer size overwrites adjacent stack memory, including potentially the saved return address. For detailed technical analysis, refer to Bugzilla Report #28768.

Detection Methods for CVE-2022-23218

Indicators of Compromise

• Unusual crashes in applications using RPC functionality with stack corruption signatures
• Core dumps showing buffer overflow patterns in glibc sunrpc module functions
• Segmentation faults originating from svcunix_create or related RPC functions
• Evidence of abnormally long socket path strings in application logs or memory

Detection Strategies

• Monitor for application crashes with stack smashing detected errors related to RPC services
• Implement file integrity monitoring on glibc shared libraries to detect unauthorized modifications
• Use runtime application self-protection (RASP) solutions to detect buffer overflow attempts
• Deploy network intrusion detection rules to identify malformed RPC requests with oversized path parameters

Monitoring Recommendations

• Enable crash reporting and analysis for services utilizing Sun RPC functionality
• Implement centralized logging for RPC service events and correlate with security monitoring
• Use SentinelOne's behavioral AI to detect anomalous memory access patterns indicative of exploitation attempts
• Configure alerts for unexpected termination of RPC-dependent services

How to Mitigate CVE-2022-23218

Immediate Actions Required

• Update glibc to a patched version that addresses CVE-2022-23218
• Ensure all applications are compiled with stack protector flags enabled (-fstack-protector-strong or -fstack-protector-all)
• Audit applications for use of the deprecated svcunix_create function and migrate to secure alternatives
• Apply vendor patches from Oracle and Debian for affected products

Patch Information

Patches are available from multiple vendors. Organizations should apply updates based on their deployment environment:

• GNU glibc: Upgrade to a version newer than 2.34 that includes the security fix
• Oracle Products: Apply updates from the Oracle Security Alert July 2022
• Debian Linux: Apply updates as described in the Debian LTS Announcement
• Gentoo Linux: Follow remediation guidance in Gentoo GLSA 202208-24

Workarounds

• Disable or restrict access to services that rely on Sun RPC functionality if not required
• Implement network segmentation to limit exposure of RPC services to trusted networks only
• Use application-level firewall rules to filter abnormally long path inputs to RPC services
• Consider containerization with read-only filesystems to limit exploitation impact

# Verify glibc version and check for stack protector compilation
ldd --version
readelf -s /lib/x86_64-linux-gnu/libc.so.6 | grep svcunix_create

# Ensure applications are compiled with stack protector
gcc -fstack-protector-strong -o application application.c