CVE-2001-0736 in pine
Summary
by MITRE
Vulnerability in (1) pine before 4.33 and (2) the pico editor, included with pine, allows local users local users to overwrite arbitrary files via a symlink attack.
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Analysis
by VulDB Data Team • 11/12/2024
The vulnerability identified as CVE-2001-0736 represents a critical security flaw affecting the pine email client and its accompanying pico text editor, specifically impacting versions prior to 4.33. This issue stems from inadequate handling of temporary files during the editor's operation, creating a significant attack surface for local users seeking to exploit the system. The vulnerability manifests when the editor creates temporary files with predictable naming conventions, making them susceptible to symbolic link manipulation attacks that can lead to arbitrary file overwrites. This flaw operates under the broader category of insecure temporary file creation practices that have been extensively documented in cybersecurity literature and categorized under CWE-377. The attack vector specifically targets local users who possess the ability to create symbolic links in directories where the editor operates, allowing them to redirect the editor's file writing operations to arbitrary locations within the filesystem.
The technical implementation of this vulnerability exploits the fundamental weakness in how temporary files are managed during the editor's execution lifecycle. When pine or pico creates temporary files, it typically uses predictable names and locations that can be anticipated by an attacker. Local users can create symbolic links with these predictable names in the directories where the editor operates, effectively intercepting the file creation process. This technique, known as a symlink attack or race condition exploit, allows attackers to manipulate the editor's behavior to write content to files of their choosing rather than the intended target. The vulnerability specifically affects systems where the editor lacks proper validation mechanisms to detect such symbolic link manipulations, often occurring in environments where users have limited but sufficient privileges to create symbolic links in the relevant directories. The flaw essentially violates the principle of least privilege by allowing local users to bypass normal file access controls and potentially overwrite critical system files or user data.
The operational impact of CVE-2001-0736 extends beyond simple file overwrites to potentially compromise system integrity and confidentiality. An attacker exploiting this vulnerability could overwrite configuration files, system binaries, or sensitive user data with malicious content, potentially leading to privilege escalation or persistent backdoor installations. The vulnerability's classification aligns with ATT&CK technique T1059 which covers command and scripting interpreters, as the compromised editor could be used to execute malicious code through the overwritten files. Additionally, this flaw contributes to broader attack chains involving privilege escalation and persistence mechanisms, particularly when attackers can overwrite system-critical files such as those in /etc or other sensitive directories. The vulnerability also represents a significant concern for multi-user systems where local users might attempt to exploit this weakness to gain unauthorized access to other users' data or system resources. Organizations using affected versions of pine and pico were particularly vulnerable during the early 2000s when such email clients were widely deployed in enterprise and academic environments.
Mitigation strategies for CVE-2001-0736 involve both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities. The primary and most effective solution is to upgrade to pine version 4.33 or later, where the developers implemented proper temporary file handling mechanisms that prevent symbolic link attacks. System administrators should also implement proper file system permissions and directory access controls to limit the ability of local users to create symbolic links in critical directories. Additional mitigations include implementing the principle of least privilege by ensuring that the editor runs with minimal required permissions and by using secure temporary file creation methods that employ random naming conventions or atomic file creation techniques. The vulnerability serves as a classic example of why secure coding practices must include proper temporary file management, and it aligns with industry standards such as the OWASP Secure Coding Practices that emphasize the importance of avoiding predictable temporary file names and implementing proper input validation. Organizations should also consider implementing intrusion detection systems that monitor for unusual file creation patterns or unauthorized file modifications that might indicate exploitation attempts. Regular security audits and vulnerability assessments should specifically target applications that handle temporary files to identify similar weaknesses that could be exploited in the future.