CVE-2022-41318 in Web Proxy
Summary
by MITRE • 12/26/2022
A buffer over-read was discovered in libntlmauth in Squid 2.5 through 5.6. Due to incorrect integer-overflow protection, the SSPI and SMB authentication helpers are vulnerable to reading unintended memory locations. In some configurations, cleartext credentials from these locations are sent to a client. This is fixed in 5.7.
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Analysis
by VulDB Data Team • 05/20/2025
The vulnerability CVE-2022-41318 represents a critical buffer over-read condition within the libntlmauth component of Squid proxy software versions 2.5 through 5.6. This flaw specifically affects the SSPI and SMB authentication helpers that are integral to Squid's authentication infrastructure. The vulnerability stems from inadequate integer overflow protection mechanisms that fail to properly validate boundary conditions during memory allocation operations. According to CWE-129, this represents an implementation flaw where the software does not correctly handle cases where an integer value exceeds the maximum value that can be stored in the corresponding data type, leading to unexpected behavior in memory management operations. The vulnerability exists in the authentication processing pipeline where the software attempts to read from memory locations beyond the intended buffer boundaries.
The technical exploitation of this vulnerability occurs when the authentication helpers process NTLM authentication requests through SSPI or SMB protocols. During these operations, the software performs integer calculations to determine buffer sizes for memory allocation, but fails to properly validate these calculations against potential overflow conditions. When an attacker crafts malicious authentication requests with carefully constructed parameters, the integer overflow causes the software to access memory locations that were not intended for the current operation. This over-read behavior allows the system to potentially expose sensitive data from adjacent memory regions, including cleartext credentials that may be present in these unintended memory locations. The vulnerability demonstrates characteristics consistent with ATT&CK technique T1550.001, where adversaries exploit authentication mechanisms to gain access to credentials and sensitive information.
The operational impact of CVE-2022-41318 extends beyond simple memory access violations, as it creates potential credential exposure scenarios within network environments that rely on Squid's authentication infrastructure. Organizations using affected Squid versions may experience unauthorized access to cleartext credentials that could be transmitted to client systems through the authentication process. The vulnerability affects authentication flows that are commonly used in enterprise environments where Squid serves as a proxy server for web traffic and authentication services. The exposure of cleartext credentials represents a significant risk to network security, as these credentials could be leveraged for lateral movement and privilege escalation attacks. Network administrators should consider the broader implications for their authentication infrastructure, particularly in environments where Squid is used for authentication proxy services.
The mitigation strategy for CVE-2022-41318 requires immediate deployment of Squid version 5.7 or later, which contains the necessary patches to address the integer overflow protection mechanisms. Organizations should also implement network monitoring to detect potential exploitation attempts through unusual authentication traffic patterns. Security teams should review their authentication configurations to ensure that only necessary authentication helpers are enabled, reducing the attack surface. The fix addresses the root cause by implementing proper integer overflow checks and boundary validations in the memory allocation routines. Additionally, organizations should conduct vulnerability assessments to identify other systems that may be running affected Squid versions and ensure comprehensive patch management across their infrastructure. The resolution aligns with security best practices for preventing buffer over-read vulnerabilities and maintaining secure authentication processes as outlined in industry standards and frameworks.