CVE-2008-4555 in Graphviz
Summary
by MITRE
Stack-based buffer overflow in the push_subg function in parser.y (lib/graph/parser.c) in Graphviz 2.20.2, and possibly earlier versions, allows user-assisted remote attackers to cause a denial of service (memory corruption) or execute arbitrary code via a DOT file with a large number of Agraph_t elements.
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Analysis
by VulDB Data Team • 08/02/2021
The vulnerability described in CVE-2008-4555 represents a critical stack-based buffer overflow affecting Graphviz version 2.20.2 and potentially earlier releases. This flaw exists within the push_subg function located in the parser.y file at lib/graph/parser.c, which is part of the graph parsing infrastructure that processes DOT files used for representing graph structures. The vulnerability arises from inadequate input validation and buffer size management when handling Agraph_t elements within DOT file parsing operations, creating a scenario where maliciously crafted input can overwrite adjacent stack memory.
The technical implementation of this vulnerability stems from the function's failure to properly bounds-check the number of Agraph_t elements that can be processed during DOT file parsing. When a user-assisted remote attacker provides a DOT file containing an excessive number of these graph elements, the push_subg function attempts to store these elements on the stack without sufficient validation of the input size. This results in a classic stack buffer overflow condition where the function's local variables and return addresses become corrupted, potentially allowing an attacker to manipulate program execution flow. The vulnerability operates under CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1203 for legitimate program exploitation through buffer overflows.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential arbitrary code execution capabilities. When successfully exploited, the buffer overflow can cause memory corruption that leads to unpredictable program behavior, including crashes, memory corruption, or more severely, remote code execution. The remote aspect of the attack means that an attacker does not need physical access to the target system, as the vulnerability can be triggered through network-delivered DOT files. This makes the vulnerability particularly dangerous in environments where Graphviz is used to process untrusted input, such as web applications, email attachments, or collaborative platforms that accept graph file uploads. The memory corruption effects can manifest as application crashes or more insidiously, allow attackers to inject and execute malicious code with the privileges of the affected process.
Mitigation strategies for CVE-2008-4555 should prioritize immediate patching of affected Graphviz installations to versions that address the buffer overflow vulnerability. System administrators should implement input validation measures to limit the size and complexity of DOT files processed by Graphviz applications, particularly in multi-user or web-based environments. Additionally, deploying runtime protections such as stack canaries, address space layout randomization, and non-executable stack protections can help mitigate exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems running Graphviz to untrusted inputs, while monitoring for suspicious file processing activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and bounds checking in parsing functions, particularly when handling structured data formats that may contain recursive or nested elements.