CVE-2010-2072 in Pyftpd
Summary
by MITRE
Pyftpd 0.8.4 creates log files with predictable names in a temporary directory, which allows local users to cause a denial of service and obtain sensitive information.
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Analysis
by VulDB Data Team • 02/06/2019
The vulnerability identified as CVE-2010-2072 affects Pyftpd version 0.8.4 and represents a significant security flaw related to improper temporary file handling. This issue stems from the application's tendency to create log files with predictable naming conventions within temporary directories, creating opportunities for local attackers to exploit the system's file management mechanisms. The vulnerability is classified under CWE-377 as "Insecure Temporary File Creation" and falls within the broader category of insecure file handling practices that have been consistently documented in security frameworks and standards. The predictable nature of these temporary file names creates a race condition vulnerability where malicious users can anticipate and manipulate the file creation process to gain unauthorized access to sensitive information or disrupt system operations.
The technical flaw manifests when Pyftpd generates log files using static or easily guessable naming patterns that do not incorporate sufficient randomness or unique identifiers. This predictable file naming scheme allows local users to monitor the temporary directory for the creation of these log files and subsequently access them to extract sensitive information that may include user credentials, session data, or other confidential operational details. The vulnerability is particularly concerning because it operates at the file system level, leveraging the fundamental weakness in how temporary files are managed rather than exploiting application logic flaws. Attackers can leverage this weakness to perform information disclosure attacks by reading the contents of these predictable log files, or alternatively use the predictable file names to overwrite existing files or create symbolic links that redirect the application's logging behavior to malicious destinations.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to denial of service conditions when local users manipulate the temporary file creation process to exhaust system resources or corrupt the logging mechanism. The attack surface is particularly wide given that Pyftpd is a file transfer protocol server implementation that typically runs with elevated privileges, making the potential damage from this vulnerability more severe. The vulnerability aligns with ATT&CK technique T1078 for Valid Accounts and T1005 for Data from Local System, as it allows for both privilege escalation through information gathering and system disruption through resource exhaustion. Organizations running affected versions of Pyftpd are exposed to potential data breaches where sensitive information stored in temporary log files could be accessed by unauthorized local users, while the denial of service component can disrupt critical file transfer operations.
Mitigation strategies for CVE-2010-2072 should focus on implementing secure temporary file creation practices that eliminate predictable naming patterns and ensure proper file permissions are enforced. The most effective approach involves modifying the application to use cryptographically secure randomization when generating temporary file names and ensuring that these files are created with restrictive permissions that prevent unauthorized access. System administrators should also implement proper directory permissions and monitoring for the temporary directories used by Pyftpd, while considering the adoption of more secure logging mechanisms that do not rely on temporary file creation for their operation. The vulnerability highlights the importance of following secure coding practices and implementing proper input validation and file handling procedures, as outlined in OWASP Top 10 and NIST cybersecurity guidelines. Additionally, regular security audits and code reviews should specifically examine temporary file handling mechanisms to identify similar vulnerabilities that may exist in other applications within the system. Organizations should also consider implementing automated monitoring solutions that can detect and alert on suspicious file creation patterns in temporary directories, providing an additional layer of defense against this type of exploitation.