CVE-2017-9406 in Poppler
Summary
by MITRE
In Poppler 0.54.0, a memory leak vulnerability was found in the function gmalloc in gmem.cc, which allows attackers to cause a denial of service via a crafted file.
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Analysis
by VulDB Data Team • 05/25/2020
The vulnerability identified as CVE-2017-9406 represents a critical memory management flaw within the Poppler PDF rendering library version 0.54.0. This issue manifests as a memory leak in the gmalloc function located within the gmem.cc source file, demonstrating a fundamental weakness in how the library handles dynamic memory allocation during PDF processing operations. The flaw occurs when the library encounters specifically crafted PDF files that trigger improper memory deallocation patterns, leading to gradual memory consumption that can ultimately exhaust available system resources.
The technical nature of this vulnerability aligns with CWE-401, which categorizes memory leaks as a well-known weakness in software systems. When Poppler processes maliciously constructed PDF documents, the gmalloc function fails to properly release allocated memory blocks, causing the application to retain memory that should have been freed. This memory retention occurs repeatedly during processing of malformed input files, creating a cumulative effect that can lead to system instability and resource exhaustion. The vulnerability specifically affects the memory management subsystem of the PDF rendering engine, where the library's allocation and deallocation mechanisms become inconsistent under certain input conditions.
From an operational perspective, this vulnerability presents a significant denial of service risk to systems utilizing Poppler for PDF processing. Attackers can exploit this flaw by crafting specially designed PDF files that, when opened or processed by applications built on Poppler, cause progressive memory consumption until system performance degrades or crashes occur. The impact extends beyond individual application failures to potentially affect entire systems or services that rely on PDF handling capabilities, particularly in server environments where multiple PDF operations occur simultaneously. This vulnerability can be particularly dangerous in automated processing environments or web applications where PDF files are frequently handled without proper input validation.
The mitigation strategy for CVE-2017-9406 primarily involves upgrading to a patched version of the Poppler library where the memory leak in the gmalloc function has been resolved. System administrators should prioritize updating their Poppler installations to versions that address this specific memory management issue, as the vulnerability can be exploited remotely through PDF file processing. Additionally, implementing input validation controls and sandboxing mechanisms for PDF handling processes can provide defensive measures while waiting for full patch deployment. Organizations should also consider monitoring system memory usage patterns for applications utilizing Poppler, as unusual memory consumption trends can indicate exploitation attempts. This vulnerability demonstrates the importance of proper memory management practices in security-critical libraries and aligns with ATT&CK technique T1499.004 for resource exhaustion attacks through memory leaks in system components.