CVE-2012-5303 in HTTP Daemon
Summary
by MITRE
Monkey HTTP Daemon 0.9.3 might allow local users to overwrite arbitrary files via a symlink attack on a PID file, as demonstrated by a pathname different from the default /var/run/monkey.pid pathname.
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Analysis
by VulDB Data Team • 02/06/2018
The vulnerability identified as CVE-2012-5303 affects the Monkey HTTP Daemon version 0.9.3, presenting a significant local privilege escalation risk through a symlink attack mechanism. This flaw specifically targets the daemon's handling of PID files during the startup process, creating an opportunity for malicious local users to manipulate system file permissions and potentially overwrite critical system files. The vulnerability manifests when the daemon creates or modifies a PID file without proper validation of the target file path, particularly when the default location /var/run/monkey.pid is not used. This represents a classic race condition vulnerability where the timing of file operations creates an exploitable window for attackers to substitute a legitimate PID file with a symbolic link pointing to a target file of their choosing. The attack vector leverages the principle of least privilege by exploiting the daemon's assumption that it can safely create or modify files in designated locations without verifying the integrity of the file system path.
The technical implementation of this vulnerability stems from improper file handling procedures within the Monkey HTTP Daemon's startup routine, where the application does not adequately validate or sanitize the path specified for PID file creation. When a user can control or influence the path where the PID file is stored, and the daemon does not perform proper checks to ensure that the target location is not a symbolic link, an attacker can establish a symlink pointing to a sensitive system file before the daemon attempts to write to it. This creates a window where the daemon's write operation actually modifies the target file referenced by the symlink rather than the intended PID file, potentially allowing the attacker to modify system configuration files, binaries, or other critical resources. The vulnerability aligns with CWE-377, which addresses insecure temporary file handling, and CWE-378, which covers the creation of insecure temporary files, both of which are commonly exploited in privilege escalation attacks. From an operational perspective, this vulnerability could be classified under the MITRE ATT&CK framework's privilege escalation techniques, specifically targeting the T1068 - Exploitation for Privilege Escalation tactic.
The impact of this vulnerability extends beyond simple file overwrites, as it can enable attackers to modify system-critical files that may lead to persistent access or system compromise. Local users who can execute the attack can potentially escalate their privileges to the daemon's user context or even root if the daemon runs with elevated permissions. The exploitation requires minimal privileges since it only involves local file system manipulation and does not require network access or complex remote exploitation techniques. The vulnerability is particularly concerning in environments where the Monkey HTTP Daemon is used with elevated privileges or where local users have the ability to influence the daemon's startup parameters. The default configuration of the daemon may be secure, but any deviation from the standard path creates a potential attack surface that can be exploited by adversaries. Organizations should consider this vulnerability as part of their overall security posture assessment, particularly in environments where local privilege escalation is a concern and where the Monkey HTTP Daemon is deployed with elevated privileges or in multi-user environments where local attackers may exist. The vulnerability demonstrates the importance of proper input validation and secure file handling practices, emphasizing the need for applications to validate file paths and ensure that file system operations are performed securely to prevent attackers from manipulating the intended target of file operations.