CVE-2005-3191 in Xpdf
Summary
by MITRE
Multiple heap-based buffer overflows in the (1) DCTStream::readProgressiveSOF and (2) DCTStream::readBaselineSOF functions in the DCT stream parsing code (Stream.cc) in xpdf 3.01 and earlier, as used in products such as (a) Poppler, (b) teTeX, (c) KDE kpdf, (d) pdftohtml, (e) KOffice KWord, (f) CUPS, and (g) libextractor allow user-assisted attackers to cause a denial of service (heap corruption) and possibly execute arbitrary code via a crafted PDF file with an out-of-range number of components (numComps), which is used as an array index.
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Analysis
by VulDB Data Team • 07/06/2021
The vulnerability described in CVE-2005-3191 represents a critical heap-based buffer overflow affecting the DCTStream parsing functionality within xpdf version 3.01 and earlier. This issue manifests in two distinct functions within the Stream.cc file: DCTStream::readProgressiveSOF and DCTStream::readBaselineSOF, which are responsible for processing Discrete Cosine Transform streams in PDF files. The flaw occurs when processing JPEG-encoded image data embedded within PDF documents, specifically when the number of components parameter exceeds valid bounds during stream parsing operations.
The technical exploitation of this vulnerability stems from improper bounds checking within the DCT stream parsing code where an attacker can craft a malicious PDF file containing an out-of-range number of components value. This invalid numComps parameter is subsequently used as an array index without adequate validation, leading to heap corruption when the application attempts to access memory locations beyond the allocated buffer boundaries. The vulnerability falls under CWE-129, which specifically addresses insufficient validation of length of inputs, and more broadly under CWE-787, representing out-of-bounds write operations.
The operational impact of this vulnerability extends across numerous software products that utilize xpdf libraries, including Poppler, teTeX, KDE kpdf, pdftohtml, KOffice KWord, CUPS, and libextractor. When exploited, the buffer overflow can result in immediate denial of service conditions through heap corruption, causing applications to crash or become unstable. More critically, the heap corruption may enable remote code execution under certain conditions, allowing attackers to potentially execute arbitrary code with the privileges of the affected application. This makes the vulnerability particularly dangerous in server environments where PDF processing occurs without proper user interaction requirements.
The attack vector requires user-assisted exploitation, meaning an attacker must convince a user to open a specifically crafted PDF file, though this can occur through various social engineering methods or automated processing of malicious documents. The vulnerability's exploitation aligns with ATT&CK technique T1203, which covers exploitation of remote services, and T1068, covering exploitation of remote services for privilege escalation. Organizations using affected software should implement immediate patching strategies, as the vulnerability affects core PDF processing functionality that is widely deployed across desktop and server environments.
Mitigation strategies should include immediate deployment of patched versions of affected software, implementation of PDF file validation and sanitization processes, and network-based restrictions that prevent automatic processing of untrusted PDF documents. Additionally, system administrators should consider implementing sandboxing mechanisms around PDF processing applications to limit potential damage from successful exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation in multimedia processing libraries, where malformed data can lead to severe memory corruption issues affecting entire application stacks.