CVE-2007-6211 in sing
Summary
by MITRE
Send ICMP Nasty Garbage (sing) on Debian GNU/Linux allows local users to append to arbitrary files and gain privileges via the -L (output log file) option. NOTE: this issue is only a vulnerability in limited environments, since sing is not installed setuid, and the administrator would need to override a non-setuid default during installation.
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Analysis
by VulDB Data Team • 01/04/2025
The vulnerability described in CVE-2007-6211 pertains to the send icmp nasty garbage utility known as sing on Debian GNU/Linux systems. This issue represents a local privilege escalation vulnerability that arises from improper handling of file operations when the utility is invoked with specific command-line options. The vulnerability specifically manifests when the -L option is utilized to specify an output log file, creating a scenario where malicious local users can manipulate file permissions and content to achieve unauthorized privilege escalation.
The technical flaw stems from the implementation of the sing utility's file handling mechanism when processing the -L parameter. When users specify a log file path using this option, the application fails to properly validate or secure the file operations, allowing for arbitrary file append operations. This behavior creates a path traversal and file manipulation vulnerability that can be exploited by local attackers to inject malicious content into specified files or to manipulate existing files in ways that could lead to privilege elevation. The vulnerability is classified under CWE-73 as improper neutralization of special elements used in resource identifiers, specifically in the context of file path handling.
The operational impact of this vulnerability is significant within the limited scope where it can be exploited. While the sing utility itself is not installed with setuid privileges, the vulnerability becomes exploitable when system administrators override the default non-setuid installation behavior. This creates a dangerous scenario where local users can potentially leverage the utility's file handling to append content to system-critical files or to files owned by other users, depending on the system configuration and file permissions. The attack vector requires local system access and specific installation configurations, but once exploited, could allow for privilege escalation to higher-privileged user accounts or system-level access.
Mitigation strategies for this vulnerability focus primarily on proper system administration practices and configuration management. System administrators should ensure that the sing utility is installed with appropriate permissions and should avoid overriding the default non-setuid behavior unless absolutely necessary. The recommended approach involves reviewing and securing the installation parameters of the utility, ensuring that the -L option cannot be abused through improper file path handling. Additionally, implementing proper file access controls and monitoring for unauthorized file modifications can help detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1068 which covers 'Local Privilege Escalation' and specifically addresses the use of system utilities with improper file handling as a means for privilege elevation. Regular system audits and security assessments should be conducted to identify installations that may have been configured to allow for such exploitation paths, and proper security patches should be applied to address the underlying file handling implementation issues.