CVE-2007-4044 in Linux
Summary
by MITRE
** REJECT ** The MS-RPC functionality in smbd in Samba 3 on SUSE Linux before 20070720 does not include "one character in the shell escape handling." NOTE: this issue was originally characterized as a shell metacharacter issue due to an incomplete fix for CVE-2007-2447, which was interpreted by CVE to be security relevant. However, SUSE and Red Hat have disputed the problem, stating that the only impact is that scripts will not be executed if they have a "c" in their name, but even this limitation might not exist. This does not have security implications, so should not be included in CVE.
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Analysis
by VulDB Data Team • 04/14/2019
The vulnerability identified as CVE-2007-4044 represents a classification dispute within the cybersecurity community regarding the true security implications of a flaw in Samba's MS-RPC functionality. This issue specifically affected smbd service components running on SUSE Linux systems before the 20070720 update, where the shell escape handling mechanism contained what was described as "one character" - specifically the letter 'c' - in its implementation. The vulnerability was initially categorized as a shell metacharacter issue due to an incomplete remediation of CVE-2007-2447, which demonstrates the complexity of vulnerability classification and the potential for cascading issues in security patching processes. The original characterization of this flaw as security-relevant was based on the premise that improper shell escape handling could potentially allow for command injection attacks, a concern that aligns with CWE-78 which addresses improper neutralization of special elements used in OS commands.
The operational impact of this vulnerability, as assessed by both SUSE and Red Hat, was deemed minimal and non-security-relevant. The primary consequence was that scripts containing the letter 'c' in their filenames would not execute properly, though even this limitation was questioned by the vendors. This assessment places the vulnerability in the context of CWE-20, which deals with improper input validation, as the core issue involved how the system handled certain character inputs during shell command processing. The vulnerability's classification as non-security-relevant reflects the industry standard approach of evaluating actual threat impact rather than theoretical attack surface considerations. The distinction between a potential security issue and a functional limitation becomes critical in vulnerability management, as resources are allocated differently based on the severity classification.
The technical nature of this flaw relates to how Samba's smbd service processes remote procedure calls and handles shell escape sequences, which is fundamental to the service's operation. This type of issue typically falls under the ATT&CK framework's technique T1059.001 for Command and Scripting Interpreter, specifically when commands are executed through shell interfaces. The fact that this vulnerability was ultimately rejected from CVE status indicates that the security community determined the risk was too low to warrant public disclosure or inclusion in the official vulnerability database. This decision aligns with security best practices where false positives or low-impact issues are not included in CVE databases to prevent unnecessary alarm and resource allocation. The issue demonstrates how vulnerability assessment requires careful evaluation of actual attack vectors, impact scope, and real-world exploitation potential rather than merely identifying potential code flaws. The resolution involved proper implementation of shell escape handling that correctly processes all characters, including the problematic 'c' character, thereby eliminating the functional limitation without introducing new security concerns. This case study illustrates the importance of thorough testing and validation of security patches, as well as the need for clear communication between vendors and security organizations regarding vulnerability classification and impact assessment.