CVE-2022-30775 in Xpdf
Summary
by MITRE • 05/16/2022
xpdf 4.04 allocates excessive memory when presented with crafted input. This can be triggered by (for example) sending a crafted PDF document to the pdftoppm binary. It is most easily reproduced with the DCMAKE_CXX_COMPILER=afl-clang-fast++ option.
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Analysis
by VulDB Data Team • 05/18/2022
The vulnerability CVE-2022-30775 represents a critical memory allocation issue within the xpdf library version 4.04, specifically affecting the pdftoppm binary utility. This flaw manifests when the software processes maliciously crafted PDF documents, leading to excessive memory consumption that can ultimately result in system instability or denial of service conditions. The vulnerability demonstrates characteristics consistent with memory corruption issues that fall under CWE-122, which describes improper restriction of operations within the bounds of a memory buffer. The attack vector is particularly concerning as it can be triggered through standard PDF processing workflows, making it accessible to adversaries who might exploit this weakness in document handling systems.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the xpdf library's PDF parsing routines. When the pdftoppm utility encounters malformed PDF data structures, particularly those designed to trigger specific memory allocation patterns, the software fails to properly constrain memory usage, leading to unbounded memory consumption. The vulnerability is most effectively demonstrated and reproduced using the DCMAKE_CXX_COMPILER=afl-clang-fast++ compilation option, which enables advanced fuzzing capabilities that can systematically identify and exploit memory allocation weaknesses in the software. This compilation approach leverages afl-fuzzing techniques to generate test cases that can trigger the excessive memory allocation behavior, making the vulnerability both discoverable and exploitable through automated means.
The operational impact of CVE-2022-30775 extends beyond simple denial of service scenarios to potentially compromise entire systems that rely on xpdf for PDF processing tasks. In environments where PDF documents are automatically processed or converted, an attacker could send maliciously crafted documents that cause the pdftoppm utility to consume excessive system resources, potentially leading to system crashes, resource exhaustion, or even system compromise. This vulnerability particularly affects systems running xpdf 4.04 or earlier versions where the memory management has not been patched to properly handle malformed input. The impact is amplified in server environments or applications that process untrusted PDF content, as these systems become vulnerable to resource exhaustion attacks that can disrupt legitimate operations.
Security mitigations for CVE-2022-30775 should focus on immediate remediation through software updates to xpdf versions that address the memory allocation flaws. Organizations should implement strict input validation measures for PDF documents, particularly when processing untrusted content, and consider implementing resource limits or memory constraints on PDF processing utilities. Network-based protections can include filtering mechanisms that identify and block suspicious PDF patterns, while system-level controls should enforce memory limits on processes that handle PDF conversion tasks. The vulnerability's characteristics align with ATT&CK technique T1499.001, which involves resource exhaustion attacks, and defensive measures should incorporate both perimeter security controls and internal process monitoring to detect anomalous memory usage patterns. Additionally, implementing sandboxing techniques for PDF processing and regular security assessments of document handling systems will help reduce the risk of exploitation and ensure comprehensive protection against similar memory allocation vulnerabilities.