CVE-2014-9157 in Graphviz
Summary
by MITRE
Format string vulnerability in the yyerror function in lib/cgraph/scan.l in Graphviz allows remote attackers to have unspecified impact via format string specifiers in unknown vector, which are not properly handled in an error string.
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Analysis
by VulDB Data Team • 07/19/2024
The CVE-2014-9157 vulnerability represents a critical format string vulnerability within the Graphviz software suite, specifically within the lib/cgraph/scan.l component that handles lexical scanning operations. This vulnerability exists in the yyerror function, which is responsible for error handling during the parsing of graph data structures. The flaw occurs when the software processes unknown vector data types that contain format string specifiers, leading to improper handling of these special characters within error message generation. The vulnerability demonstrates a classic buffer manipulation issue where user-controlled input directly influences the format string processing mechanism, creating potential for arbitrary code execution or information disclosure.
The technical implementation of this vulnerability stems from the improper sanitization of user input within the lexical scanner component of Graphviz. When the yyerror function encounters malformed or unexpected vector data, it attempts to format error messages without adequate validation or escaping of format specifiers such as %s, %d, or %x that may be present in the input. This creates a scenario where attackers can inject malicious format specifiers that, when processed by the printf-family functions, can cause the application to read from memory locations, write to arbitrary addresses, or execute unintended code sequences. The vulnerability specifically affects the parsing of graph data structures that utilize vector formats, making it particularly dangerous in environments where Graphviz processes untrusted input from external sources.
The operational impact of CVE-2014-9157 extends beyond simple privilege escalation or denial of service scenarios, potentially enabling remote code execution on systems running vulnerable Graphviz installations. Attackers can exploit this vulnerability by crafting specially formatted graph files or vector data that contain malicious format specifiers, which are then processed by the yyerror function during parsing operations. This threat model aligns with ATT&CK technique T1203 for exploitation of vulnerabilities and CWE-134 which specifically addresses format string vulnerabilities where format strings are constructed from user-controlled data. The vulnerability's remote exploitability makes it particularly dangerous in web applications or services that utilize Graphviz for graph visualization, as attackers can remotely compromise systems through crafted input files without requiring local access.
Mitigation strategies for CVE-2014-9157 should focus on immediate patching of vulnerable Graphviz installations to ensure the latest security updates are applied. System administrators should implement input validation and sanitization measures that prevent format specifiers from being processed within error handling functions, particularly in areas that process external or untrusted data. The implementation of proper memory protection mechanisms such as stack canaries, address space layout randomization, and non-executable stack protections can help reduce the impact of successful exploitation attempts. Additionally, network segmentation and access controls should be enforced to limit exposure of Graphviz services to untrusted networks, while monitoring systems should be deployed to detect anomalous parsing behavior or unexpected memory access patterns that may indicate exploitation attempts. Organizations should also consider implementing automated vulnerability scanning processes to identify and remediate similar vulnerabilities across their software infrastructure.