CVE-2016-8387 in Argus
Summary
by MITRE
An exploitable heap-based buffer overflow exists in Iceni Argus. When it attempts to convert a malformed PDF with an object encoded w/ multiple encoding types terminating with an LZW encoded type, an overflow may occur due to a lack of bounds checking by the LZW decoder. This can lead to code execution under the context of the account of the user running it.
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Analysis
by VulDB Data Team • 09/02/2020
The vulnerability described in CVE-2016-8387 represents a critical heap-based buffer overflow within Iceni Argus software, a PDF processing tool that handles document conversion and manipulation tasks. This flaw arises specifically during the handling of malformed PDF files containing objects with complex encoding structures that combine multiple encoding types before concluding with LZW encoding. The vulnerability demonstrates a fundamental failure in input validation and memory management practices within the software's PDF parsing engine.
The technical implementation of this vulnerability stems from the LZW decoder's insufficient bounds checking mechanisms when processing encoded PDF objects. When the software encounters a PDF object that employs multiple encoding methods with LZW as the final encoding type, the decoder fails to properly validate the boundaries of allocated memory buffers. This lack of proper boundary validation allows an attacker to craft malicious PDF content that deliberately exceeds the allocated buffer space, causing a heap overflow condition. The vulnerability operates at the intersection of multiple security domains including memory corruption, input sanitization, and code execution, making it particularly dangerous for exploitation purposes.
The operational impact of this vulnerability extends beyond simple data corruption, as successful exploitation can result in arbitrary code execution with the privileges of the user account running the Iceni Argus application. This presents a significant risk in enterprise environments where such tools might be executed with elevated privileges or in automated processing workflows. The vulnerability is particularly concerning because it can be triggered through normal PDF processing operations, meaning that simply opening or converting a maliciously crafted PDF file could lead to compromise. The heap overflow condition creates opportunities for attackers to manipulate memory layout, potentially leading to stack smashing, return-oriented programming attacks, or direct code injection scenarios.
From a cybersecurity perspective, this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1203, involving exploitation of software vulnerabilities for privilege escalation. The flaw represents a classic example of insufficient input validation in security-critical applications, where the software fails to properly sanitize and validate external inputs before processing them. Organizations should consider implementing defensive measures including sandboxing PDF processing environments, restricting PDF file handling capabilities, and ensuring regular updates to mitigate this class of vulnerability. The incident highlights the importance of robust memory management practices in security tools and the necessity of comprehensive input validation across all processing pipelines.
This vulnerability serves as a reminder of the critical importance of secure coding practices in document processing software and the potential for seemingly benign file format operations to become attack vectors. The lack of proper bounds checking in the LZW decoder represents a fundamental security weakness that can be exploited without requiring specialized knowledge of the underlying system architecture. The exploitability of this condition underscores the need for comprehensive security testing, including fuzzing and boundary condition testing, particularly in software components that handle untrusted input data from external sources.