CVE-2010-1160 in nano
Summary
by MITRE
GNU nano before 2.2.4 does not verify whether a file has been changed before it is overwritten in a file-save operation, which allows local user-assisted attackers to overwrite arbitrary files via a symlink attack on an attacker-owned file that is being edited by the victim.
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Analysis
by VulDB Data Team • 07/29/2024
The vulnerability identified as CVE-2010-1160 represents a critical file system security flaw within the GNU nano text editor version 2.2.3 and earlier. This issue stems from insufficient file integrity verification mechanisms during the save operation process, creating a window of opportunity for malicious actors to exploit the system through symlink attacks. The vulnerability specifically affects local users who can assist attackers in executing file overwrite operations, making it particularly dangerous in multi-user environments where privilege escalation or data corruption could occur. The flaw exists in the core file handling logic of nano, which fails to validate whether the target file path remains consistent throughout the editing session, particularly when symbolic links are involved in the file system hierarchy.
The technical implementation of this vulnerability operates through a classic race condition scenario where an attacker creates a symbolic link pointing to a target file that the victim is currently editing. When the victim saves their changes, nano performs the save operation without verifying that the file path has not been altered between the time the file was opened and when it is being saved. This allows the attacker to manipulate the file system structure in such a way that the save operation writes content to a different file than intended, potentially overwriting critical system files or sensitive user data. The vulnerability is classified as a file system race condition and maps directly to CWE-367, which addresses Time-of-Check to Time-of-Use (TOCTOU) flaws, where the system state changes between verification and execution phases.
The operational impact of CVE-2010-1160 extends beyond simple file overwrite capabilities, as it can be leveraged for more sophisticated attacks within a system. An attacker could potentially target system configuration files, log files, or even critical executables to gain unauthorized access or disrupt system operations. The vulnerability is particularly concerning in environments where users frequently edit files with elevated privileges or where nano is used in automated processes. From an attack framework perspective, this vulnerability aligns with ATT&CK technique T1059.006 for execution through shell commands and T1490 for data destruction, as the ability to overwrite arbitrary files creates multiple attack vectors for system compromise. The local user-assisted nature of the attack means that social engineering or physical access may be required to initiate the exploit, but once triggered, the consequences can be severe.
Mitigation strategies for CVE-2010-1160 focus on both immediate remediation and long-term security hardening measures. The primary solution involves upgrading to GNU nano version 2.2.4 or later, where the file verification mechanisms have been properly implemented to prevent symlink-based file overwrites. Organizations should also implement proper file system permissions and access controls to limit the potential impact of such attacks. Additional defensive measures include monitoring for suspicious file system changes, implementing file integrity monitoring solutions, and educating users about the risks of editing files in potentially compromised environments. System administrators should consider implementing mandatory access controls and privilege separation techniques to limit the damage that could occur if such vulnerabilities are exploited. The vulnerability serves as a reminder of the importance of proper file system validation in text editors and other system utilities, particularly those that handle file I/O operations in multi-user environments where security controls are paramount.