CVE-2001-0069 in dialog
Summary
by MITRE
dialog before 0.9a-20000118-3bis in Debian GNU/Linux allows local users to overwrite arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 04/07/2019
The vulnerability described in CVE-2001-0069 represents a classic file system race condition that existed in the dialog utility version 0.9a-20000118-3bis packaged with Debian GNU/Linux. This flaw specifically enabled local attackers to exploit a symlink attack mechanism that could result in arbitrary file overwrites within the system. The dialog utility, commonly used for creating text-based user interfaces in shell scripts and system administration tasks, was susceptible to this attack due to improper handling of temporary files during its execution lifecycle. The vulnerability stems from the utility's failure to properly validate file paths and verify the integrity of temporary files it creates during operation, creating a window of opportunity for malicious actors to manipulate the file system.
The technical implementation of this vulnerability involves a time-of-check to time-of-use race condition where the dialog utility first checks for the existence of a temporary file and then uses it without revalidating the file's integrity. Attackers could create symbolic links in strategic locations that would be followed by the dialog utility during its file operations, causing the utility to write data to unintended targets. This particular weakness aligns with CWE-367, which categorizes time-of-check to time-of-use race conditions as a critical security flaw. The vulnerability specifically affects the dialog utility's temporary file handling mechanisms, where the program creates temporary files without sufficient security measures to prevent symlink-based attacks, making it possible for local users to escalate their privileges or corrupt system files.
The operational impact of this vulnerability extends beyond simple file overwrites as it provides attackers with a method to manipulate system behavior through indirect means. Since dialog is commonly used in system administration scripts and package management operations, a successful exploitation could potentially compromise the integrity of critical system processes or installations. Attackers could leverage this vulnerability to overwrite configuration files, log files, or even system binaries, depending on the context in which dialog is invoked. The attack requires local system access but offers significant potential for privilege escalation or data corruption. This vulnerability demonstrates how seemingly innocuous utilities can present serious security risks when they fail to properly handle file system operations, particularly in environments where multiple users or processes interact with shared system resources.
Mitigation strategies for this vulnerability primarily involve updating to patched versions of the dialog utility where proper temporary file handling mechanisms have been implemented. System administrators should ensure that all Debian systems are updated to versions that address this race condition, typically through package manager updates that provide secure temporary file creation methods. The fix generally involves implementing atomic file creation techniques that prevent symlink attacks by using secure file creation patterns such as creating files with exclusive access permissions or using secure temporary directory mechanisms. Additionally, organizations should implement proper file system monitoring and access control measures to detect unauthorized file modifications. This vulnerability also highlights the importance of following secure coding practices for temporary file handling and demonstrates the necessity of adhering to the principle of least privilege in system design. The remediation process should include comprehensive system auditing to identify any potential exploitation attempts and ensure that all instances of the vulnerable dialog utility have been properly updated. Organizations should also consider implementing automated patch management systems to prevent similar vulnerabilities from persisting in their environments.