CVE-2004-0884 in Cyrus-SASL
Summary
by MITRE
The (1) libsasl and (2) libsasl2 libraries in Cyrus-SASL 2.1.18 and earlier trust the SASL_PATH environment variable to find all available SASL plug-ins, which allows local users to execute arbitrary code by modifying the SASL_PATH to point to malicious programs.
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Analysis
by VulDB Data Team • 05/30/2019
The vulnerability described in CVE-2004-0884 represents a critical privilege escalation flaw within the Cyrus-SASL authentication libraries that affected versions 2.1.18 and earlier. This issue stems from the improper handling of the SASL_PATH environment variable which is utilized by both libsasl and libsasl2 libraries to locate and load SASL plug-ins. The flaw creates a dangerous trust relationship where the system automatically executes code from paths specified in the environment variable without proper validation or sanitization of the input.
The technical implementation of this vulnerability exploits the fundamental design assumption that the SASL_PATH environment variable can be trusted to contain legitimate plugin locations. When local users manipulate this variable to point to malicious programs or scripts, the authentication system inadvertently loads and executes these unauthorized components with the privileges of the process that loaded them. This behavior constitutes a classic path traversal and code execution vulnerability that falls under CWE-74, which specifically addresses improper neutralization of special elements used in data queries.
From an operational perspective, this vulnerability enables local users to gain arbitrary code execution privileges on systems utilizing affected Cyrus-SASL implementations. The impact extends beyond simple privilege escalation as it can potentially allow attackers to establish persistent backdoors, escalate privileges to system-level access, or compromise the integrity of the authentication infrastructure. The vulnerability is particularly concerning because it operates at the library level, meaning that any application relying on these SASL libraries for authentication could be compromised, creating a wide attack surface across multiple services and applications.
The attack vector for this vulnerability is straightforward and requires local system access, making it particularly dangerous in environments where privilege separation is not properly enforced. According to ATT&CK framework, this vulnerability maps to T1068 which covers "Local Port Forwarding" and T1548.001 which covers "Abuse Elevation Control Mechanism: Bypass User Account Control." The flaw essentially allows attackers to bypass the intended security controls of the authentication system by manipulating the plugin loading mechanism. Organizations should note that this vulnerability is classified as a privilege escalation issue that can be exploited through environment variable manipulation, making it a common target for attackers seeking to establish persistent access to systems.
Mitigation strategies for CVE-2004-0884 should focus on immediate patching of the affected Cyrus-SASL libraries to version 2.1.19 or later where the vulnerability has been addressed. Additionally, system administrators should implement strict environment variable controls, particularly for the SASL_PATH variable, ensuring that it only points to trusted directories. The implementation of secure coding practices that validate and sanitize all environment variables, combined with proper privilege separation and access controls, can significantly reduce the risk of exploitation. Organizations should also consider monitoring for unusual patterns in environment variable modifications and implement security measures such as file integrity monitoring to detect unauthorized changes to critical authentication libraries.