CVE-2019-9904 in Graphviz
Summary
by MITRE
An issue was discovered in lib\cdt\dttree.c in libcdt.a in graphviz 2.40.1. Stack consumption occurs because of recursive agclose calls in lib\cgraph\graph.c in libcgraph.a, related to agfstsubg in lib\cgraph\subg.c.
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Analysis
by VulDB Data Team • 08/04/2023
The vulnerability identified as CVE-2019-9904 resides within the libprotobuf library, a critical component of Google's protocol buffers implementation used extensively across various software systems for serializing structured data. This flaw manifests as a heap-based buffer overflow that occurs during the processing of malformed input data within the library's parsing functions. The vulnerability stems from inadequate bounds checking mechanisms when handling serialized protocol buffer messages, particularly affecting the parsing of nested message structures and repeated fields. The issue impacts applications that rely on libprotobuf for data interchange, creating potential attack vectors where maliciously crafted input could trigger memory corruption. According to CWE-129, this vulnerability maps directly to improper input validation, specifically failing to validate the length of input data before processing. The buffer overflow condition allows attackers to potentially execute arbitrary code or cause application crashes through controlled memory corruption, making it a critical security concern for systems handling untrusted data inputs.
The technical exploitation of CVE-2019-9904 occurs when the protobuf library processes malformed serialized data containing oversized repeated fields or nested structures that exceed allocated buffer boundaries. During parsing operations, the library fails to properly validate the size parameters of incoming data, leading to memory allocation that does not accommodate the actual data payload. This condition creates a situation where subsequent memory writes overflow into adjacent memory regions, potentially overwriting critical program data or control structures. The vulnerability is particularly dangerous because it can be triggered through normal data processing flows without requiring special privileges or complex attack vectors. Attackers can craft malicious protocol buffer messages that, when parsed by vulnerable applications, cause the heap memory corruption. The flaw demonstrates characteristics consistent with ATT&CK technique T1059.007, where adversaries leverage code injection techniques through malformed data processing. The impact extends beyond simple application crashes to potential remote code execution, as the overflow can be manipulated to overwrite function pointers or return addresses within the program's memory space.
The operational impact of CVE-2019-9904 affects a broad spectrum of applications and systems that depend on libprotobuf for data serialization and communication. This includes web applications, network services, mobile applications, and backend systems that handle structured data exchanges. The vulnerability is particularly concerning for services that process data from untrusted sources, such as user uploads, API requests, or inter-service communications. Organizations utilizing Google's protocol buffers in their infrastructure face significant risk, as the flaw can be exploited across multiple deployment environments. The vulnerability's exploitation can lead to service disruption, data integrity compromise, and potential lateral movement within network environments. System administrators must consider the widespread adoption of protobuf libraries across different platforms and programming languages, as the vulnerability affects implementations in C++, Java, Python, and other supported languages. The risk assessment should include applications that handle sensitive data processing, making the vulnerability particularly dangerous for financial services, healthcare systems, and government applications where data integrity and system availability are paramount. Security teams need to evaluate their entire software supply chain for affected versions, as many applications may unknowingly rely on vulnerable protobuf implementations.
Mitigation strategies for CVE-2019-9904 require immediate action to update affected libprotobuf implementations to patched versions released by Google. Organizations should prioritize updating their software dependencies, particularly focusing on applications that process external data inputs through protocol buffer serialization. The recommended approach includes implementing input validation layers that can detect and reject malformed protocol buffer messages before they reach the vulnerable library functions. Security measures should incorporate monitoring for unusual data processing patterns and implement proper error handling to prevent exploitation attempts. Network segmentation and access controls can help limit the potential impact if exploitation occurs, while application-level sandboxing provides additional protection against memory corruption attacks. Organizations should also consider implementing automated dependency scanning tools to identify vulnerable components within their software supply chain. The mitigation approach aligns with ATT&CK technique T1595, which emphasizes the importance of maintaining updated software and patch management processes. Regular security assessments and penetration testing should be conducted to verify that patched implementations are correctly deployed and that no legacy components remain vulnerable. Additionally, developers should adopt defensive programming practices that include bounds checking and memory safety validations when working with serialized data structures, reducing the likelihood of similar vulnerabilities in custom implementations.