CVE-2014-0027 in Flite
Summary
by MITRE
The play_wave_from_socket function in audio/auserver.c in Flite 1.4 allows local users to modify arbitrary files via a symlink attack on /tmp/awb.wav. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/31/2022
The vulnerability identified as CVE-2014-0027 resides within the Flite 1.4 text-to-speech engine, specifically in the audio/auserver.c component where the play_wave_from_socket function operates. This flaw represents a classic symlink attack vulnerability that enables local attackers to manipulate file operations through improper temporary file handling. The issue manifests when the function creates or modifies files in the /tmp directory without adequate security checks, making it susceptible to race conditions and symbolic link manipulation attacks.
The technical implementation of this vulnerability stems from the function's failure to properly validate file paths and handle temporary file creation in a secure manner. When Flite processes audio data through the play_wave_from_socket function, it generates temporary files in the /tmp directory with predictable naming conventions such as awb.wav. Attackers can exploit this predictability by creating symbolic links with the same names in the /tmp directory before the legitimate file creation occurs, effectively redirecting the function's file operations to target arbitrary locations on the filesystem. This type of vulnerability falls under CWE-377 which specifically addresses insecure temporary file creation practices and can be categorized under the broader ATT&CK technique T1548.001 for privilege escalation through file permissions manipulation.
The operational impact of this vulnerability extends beyond simple file modification as it provides attackers with the ability to write to arbitrary locations within the filesystem, potentially leading to privilege escalation or system compromise. Local users who can execute the vulnerable Flite functionality can leverage this weakness to overwrite critical system files, inject malicious code into executables, or manipulate configuration files that the application or system services might later read. The vulnerability's exploitation requires local access but does not necessitate elevated privileges initially, making it particularly dangerous in multi-user environments where attackers might attempt to escalate privileges through file system manipulation. The attack vector is particularly concerning because it operates at the application level and can be triggered through normal audio processing operations.
Mitigation strategies for CVE-2014-0027 should focus on implementing secure temporary file creation practices that prevent symlink attacks and race conditions. The most effective approach involves using secure temporary file creation functions that guarantee atomic file creation with appropriate permissions, such as mkstemp or similar secure APIs that ensure file ownership and prevent symbolic link resolution. System administrators should also implement proper file system permissions and access controls to limit write access to critical directories, particularly /tmp, and consider implementing file system integrity monitoring to detect unauthorized file modifications. Additionally, the vulnerability can be addressed through patching the Flite software to version 1.5 or later where the temporary file handling has been corrected, and implementing proper input validation and path resolution checks within the audio processing components. Organizations should also conduct regular security assessments of third-party software components to identify and remediate similar vulnerabilities in their software supply chain.