CVE-2012-4455 in openCryptoki
Summary
by MITRE
openCryptoki 2.4.1 allows local users to create or set world-writable permissions on arbitrary files via a symlink attack on the (1) LCK..opencryptoki or (2) LCK..opencryptoki_stdll file in /var/lock/.
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Analysis
by VulDB Data Team • 12/19/2021
The vulnerability identified as CVE-2012-4455 affects openCryptoki version 2.4.1, a cryptographic library implementation that provides security services for cryptographic operations within Unix-like systems. This issue represents a significant privilege escalation risk that arises from improper handling of temporary files during the cryptographic service initialization process. The vulnerability specifically targets the lock file management mechanism used by openCryptoki to coordinate access to its cryptographic resources across multiple processes or threads.
The technical flaw manifests through a classic symlink attack pattern where local attackers can manipulate the creation of lock files in the /var/lock/ directory. The vulnerability exists in the handling of two specific lock files named LCK..opencryptoki and LCK..opencryptoki_stdll which are created during the service startup or operation phases. When the openCryptoki service initializes, it attempts to create these lock files without proper validation of existing symbolic links, allowing attackers to establish malicious symlinks before the legitimate files are created. This race condition vulnerability falls under CWE-367 which specifically addresses Time-of-Check to Time-of-Use (TOCTOU) flaws where the system state changes between verification and actual use of resources.
The operational impact of this vulnerability extends beyond simple file permission manipulation as it provides attackers with persistent world-writable access to arbitrary files within the system. An attacker who successfully exploits this vulnerability can not only create files with unrestricted permissions but can also overwrite existing files, potentially compromising the integrity of the cryptographic infrastructure. This attack vector is particularly dangerous because it operates at the system level where the cryptographic service runs with elevated privileges, potentially allowing attackers to modify critical system files or inject malicious code into the cryptographic subsystem. The vulnerability also aligns with ATT&CK technique T1068 which covers privilege escalation through local exploitation of system vulnerabilities.
The exploitation process involves creating symbolic links to target locations before the legitimate lock files are created, followed by triggering the service initialization or operation that causes the system to write to these controlled paths. This allows attackers to gain persistent access to system resources and potentially escalate their privileges further by modifying the cryptographic service binaries or configuration files. The vulnerability demonstrates poor security practices in temporary file handling and highlights the importance of proper file system access controls and atomic file creation operations. Organizations using openCryptoki version 2.4.1 should immediately apply patches or upgrade to versions that properly validate lock file creation and implement proper file system permissions management to prevent such symlink attacks from succeeding.
Mitigation strategies should focus on implementing proper file system permissions, using atomic file creation techniques, and ensuring that lock files are created with appropriate access controls that prevent symbolic link manipulation. System administrators should also implement monitoring for unauthorized file creation in the /var/lock/ directory and consider implementing additional security controls such as mandatory access controls or file integrity monitoring solutions to detect and prevent exploitation attempts. The vulnerability underscores the critical importance of proper input validation and file system security practices in cryptographic implementations where the compromise of system integrity can have far-reaching consequences for security infrastructure.