CVE-2006-6629 in Program Generation Language
Summary
by MITRE
lib/WeBWorK/PG/Translator.pm in WeBWorK Program Generation (PG) Language before 2.3.1 uses an insufficiently restrictive regular expression to determine valid macro filenames, which allows attackers to load arbitrary macro files whose names contain the strings (1) dangerousMacros.pl, (2) PG.pl, or (3) IO.pl.
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Analysis
by VulDB Data Team • 10/03/2017
The vulnerability identified as CVE-2006-6629 resides within the WeBWorK Program Generation language component, specifically in the lib/WeBWorK/PG/Translator.pm file. This issue affects WeBWorK versions prior to 2.3.1 and represents a critical security flaw that undermines the system's ability to properly validate macro file names. The vulnerability stems from the implementation of a regular expression that fails to adequately restrict the characters and patterns allowed in macro filenames, creating a path for malicious actors to bypass intended security controls. The flaw allows attackers to load arbitrary macro files that contain specific dangerous strings in their names, potentially enabling unauthorized code execution and system compromise.
The technical implementation of this vulnerability involves a flawed regular expression pattern that does not sufficiently validate input parameters for macro file names. When WeBWorK processes macro files, it uses this inadequate validation to determine which files can be loaded and executed within the system. The vulnerable code accepts files with names containing the strings "dangerousMacros.pl", "PG.pl", or "IO.pl" without proper authorization checks, effectively allowing attackers to include malicious code that could execute with the privileges of the WeBWorK system. This weakness directly relates to CWE-20, which addresses improper input validation, and represents a classic example of insufficient validation or sanitization of user-provided data. The regular expression implementation fails to properly restrict the filename patterns to only those that are explicitly authorized, creating a scenario where any file name containing these dangerous substrings can be loaded regardless of the file's actual location or intended purpose.
The operational impact of this vulnerability extends beyond simple code execution to encompass potential system compromise and data exposure. Attackers can leverage this flaw to load malicious macro files that may contain code injection payloads, privilege escalation mechanisms, or data exfiltration tools. The presence of "PG.pl" in the vulnerable pattern suggests that attackers could potentially load core system components with modified functionality, while "IO.pl" indicates possible access to input/output operations that could enable file system manipulation. The ability to load arbitrary macro files creates a pathway for attackers to gain unauthorized access to the WeBWorK environment, potentially allowing them to modify course content, access student data, or even compromise the underlying server infrastructure. This vulnerability aligns with ATT&CK technique T1059, which covers execution through command and scripting interpreters, and represents a significant risk to educational institutions that rely on WeBWorK for mathematical problem generation and online assessment.
The remediation for this vulnerability requires immediate implementation of proper input validation mechanisms within the WeBWorK PG Translator component. System administrators should upgrade to WeBWorK version 2.3.1 or later, where the regular expression validation has been strengthened to prevent loading of macro files containing the dangerous strings without proper authorization. Additionally, organizations should implement proper file access controls and validate all macro file names against a strict whitelist of approved components. The fix should enforce strict path validation and ensure that only authorized macro files can be loaded, eliminating the possibility of attackers exploiting the insufficiently restrictive regular expression. Security monitoring should be implemented to detect unauthorized attempts to load macro files, and access logs should be reviewed to identify any potential exploitation attempts. This vulnerability demonstrates the critical importance of proper input validation in security-critical applications and highlights the need for comprehensive security testing of all components that handle user-provided input. Organizations should also consider implementing additional security controls such as file integrity monitoring and privilege separation to further reduce the risk of exploitation.