CVE-2024-38439 in Netatalk
Summary
by MITRE • 06/16/2024
Netatalk 3.2.0 has an off-by-one error and resultant heap-based buffer overflow because of setting ibuf[PASSWDLEN] to '\0' in FPLoginExt in login in etc/uams/uams_pam.c.
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Analysis
by VulDB Data Team • 11/28/2024
The vulnerability identified as CVE-2024-38439 affects Netatalk version 3.2.0 and represents a critical heap-based buffer overflow resulting from an off-by-one error in the authentication process. This flaw exists within the File Provider Login Extension component, specifically in the FPLoginExt function located in the etc/uams/uams_pam.c source file. The issue manifests when the code attempts to set ibuf[PASSWDLEN] to a null character, creating an out-of-bounds memory write condition that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper bounds checking during password handling within the PAM authentication module. When a client attempts to authenticate through the Netatalk service, the system allocates memory for the ibuf buffer and subsequently writes beyond its allocated boundaries. The PASSWDLEN constant defines the expected buffer size, but the code incorrectly attempts to write to the position PASSWDLEN, which exceeds the valid buffer indices. This off-by-one error creates a condition where an attacker can manipulate the authentication flow to overwrite adjacent memory locations, potentially leading to arbitrary code execution or service disruption.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as it provides a potential pathway for remote code execution within the context of the Netatalk service. Attackers exploiting this flaw could gain unauthorized access to network-attached storage systems, potentially escalating privileges and compromising the entire network infrastructure. The vulnerability affects systems running Netatalk 3.2.0 where PAM authentication is enabled, making it particularly concerning for enterprise environments that rely on Apple File Protocol services for file sharing and storage management. The heap-based nature of the overflow means that memory corruption can occur in unpredictable locations, complicating exploitation but not eliminating its potential for serious damage.
Security professionals should prioritize patching affected systems immediately, as the vulnerability can be exploited remotely without authentication. The flaw aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1110.003 for credential access through brute force methods. Organizations should implement network segmentation to limit exposure and monitor for suspicious authentication attempts. The recommended mitigation includes upgrading to Netatalk versions that have addressed this buffer overflow issue, implementing proper input validation, and conducting thorough security assessments of all network services that utilize PAM authentication mechanisms. Additionally, system administrators should consider disabling unnecessary authentication modules and regularly reviewing access controls to minimize the attack surface for such vulnerabilities.