CVE-2017-2807 in Ledger-CLI
Summary
by MITRE
An exploitable buffer overflow vulnerability exists in the tag parsing functionality of Ledger-CLI 3.1.1. A specially crafted journal file can cause an integer underflow resulting in code execution. An attacker can construct a malicious journal file to trigger this vulnerability.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-2807 represents a critical buffer overflow flaw within Ledger-CLI version 3.1.1 that stems from inadequate input validation during tag parsing operations. This vulnerability falls under the category of integer underflow conditions, which occur when a decrement operation results in a value that wraps around to a much larger number than expected, creating a dangerous state where memory allocation calculations become severely miscalculated. The affected software component processes journal files containing financial transaction data, where tags are used to categorize and organize entries. When Ledger-CLI encounters malformed tag structures within these journal files, the parsing logic fails to properly validate integer values, leading to an underflow condition that can be exploited to overwrite adjacent memory locations.
The technical exploitation of this vulnerability requires careful crafting of a malicious journal file that triggers the specific integer underflow scenario during tag processing. The flaw manifests when the application attempts to allocate memory based on a computed size that becomes negative due to the underflow, creating a situation where the program allocates insufficient memory for the actual data processing. This memory mismanagement creates opportunities for attackers to overwrite critical program variables, function pointers, or return addresses within the call stack. The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates how seemingly benign input processing can create exploitable conditions that lead to arbitrary code execution. According to ATT&CK framework, this represents a privilege escalation vector through software exploitation, specifically categorized under T1068, which involves exploiting vulnerabilities in legitimate programs.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with a potential pathway to compromise systems running Ledger-CLI for financial data management. Since Ledger-CLI is commonly used for personal and business financial accounting, an exploited system could lead to unauthorized access to sensitive financial records, transaction manipulation, or complete system compromise depending on the execution environment. The vulnerability's exploitation requires only the ability to create or modify journal files, making it particularly dangerous in environments where users might process untrusted financial data or where automated systems import journal files from external sources. Organizations using Ledger-CLI for financial reporting, budgeting, or accounting processes face significant risk if they do not apply the necessary patches or updates that address this integer underflow condition. The flaw demonstrates the importance of robust input validation in financial software applications where data integrity and system security are paramount.
Mitigation strategies for CVE-2017-2807 should prioritize immediate patching of Ledger-CLI installations to version 3.1.2 or later, which contains the necessary fixes for the integer underflow condition. System administrators should implement strict file validation procedures for all journal files processed by Ledger-CLI, including automated scanning for potentially malformed tag structures that could trigger the vulnerability. Network segmentation and least privilege principles should be enforced to limit the potential impact of successful exploitation, ensuring that even if an attacker gains code execution capabilities, they cannot easily move laterally within the network. Additionally, organizations should consider implementing monitoring solutions that can detect unusual memory allocation patterns or unexpected program behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of validating all input data, particularly in financial applications where the integrity of transaction data directly impacts organizational security and compliance requirements. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other financial software components that might present analogous attack surfaces.