CVE-2007-1540 in SQL-Ledger
Summary
by MITRE
Directory traversal vulnerability in am.pl in (1) SQL-Ledger 2.6.27 and earlier, and (2) LedgerSMB before 1.2.0, allows remote attackers to run arbitrary executables and bypass authentication via a .. (dot dot) sequence and trailing NULL (%00) in the login parameter. NOTE: this issue was reportedly addressed in SQL-Ledger 2.6.27, however third-party researchers claim that the file is still executed even though an error is generated.
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Analysis
by VulDB Data Team • 10/31/2024
The vulnerability described in CVE-2007-1540 represents a critical directory traversal flaw affecting multiple accounting software applications including SQL-Ledger and LedgerSMB. This vulnerability resides in the am.pl script which processes login parameters, creating a pathway for remote attackers to execute arbitrary code on affected systems. The flaw specifically manifests when the application fails to properly validate and sanitize user input containing directory traversal sequences combined with null byte termination, allowing attackers to bypass authentication mechanisms and gain unauthorized access to system resources.
The technical implementation of this vulnerability leverages the combination of ".." directory traversal sequences with trailing NULL bytes (%00) in the login parameter. When the application processes these malformed inputs, it fails to properly sanitize the input before using it in file operations, leading to a path traversal condition. This allows attackers to navigate outside the intended directory structure and potentially access or execute files that should remain protected. The vulnerability is classified under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1078.004 for "Valid Accounts: Default Accounts" when exploitation occurs through bypassed authentication.
The operational impact of this vulnerability extends beyond simple authentication bypass, as it enables remote code execution capabilities that can lead to complete system compromise. Attackers can leverage this flaw to execute arbitrary commands on the target system, potentially gaining root or administrative privileges depending on the application's execution context. The vulnerability affects versions of SQL-Ledger up to 2.6.27 and LedgerSMB versions prior to 1.2.0, representing a significant portion of legacy accounting applications that may still be in production environments. Even though vendors claim the issue was addressed in SQL-Ledger 2.6.27, independent research has demonstrated that the vulnerability may persist due to incomplete patching or improper validation implementation.
Security professionals should consider implementing multiple layers of defense for systems running affected software versions. The recommended mitigation strategies include immediate patching of all affected applications to the latest secure versions, implementation of input validation and sanitization mechanisms, and network segmentation to limit exposure. Additionally, organizations should monitor for suspicious authentication attempts and file access patterns that may indicate exploitation attempts. The vulnerability highlights the importance of proper input validation and the dangers of relying on incomplete or improperly implemented security controls, particularly in critical business applications handling financial data. Organizations should also conduct thorough security assessments of legacy systems to identify similar path traversal vulnerabilities that may exist in other components of their infrastructure.