CVE-2019-7310 in Poppler
Summary
by MITRE
In Poppler 0.73.0, a heap-based buffer over-read (due to an integer signedness error in the XRef::getEntry function in XRef.cc) allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a crafted PDF document, as demonstrated by pdftocairo.
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Analysis
by VulDB Data Team • 07/04/2023
The vulnerability identified as CVE-2019-7310 represents a critical heap-based buffer over-read flaw within the Poppler PDF rendering library version 0.73.0. This issue stems from an integer signedness error specifically within the XRef::getEntry function located in the XRef.cc source file, demonstrating how seemingly minor coding errors can lead to significant security implications. The flaw exists in the library's handling of PDF cross-reference tables, which are fundamental structures used to organize and locate objects within PDF documents. When processing maliciously crafted PDF files, the library fails to properly validate integer values, leading to improper memory access patterns that can trigger buffer over-read conditions.
The technical exploitation of this vulnerability occurs when a PDF document contains malformed cross-reference entries that cause the XRef::getEntry function to interpret signed integer values as unsigned, resulting in incorrect memory calculations. This signedness error allows an attacker to manipulate the memory access boundaries, potentially causing the application to read beyond allocated memory regions. The vulnerability specifically affects the pdftocairo utility, which is part of the Poppler suite and used for converting PDF documents to various image formats. The flaw demonstrates characteristics consistent with CWE-128, which describes "Wrap or Overflow" conditions where signed integers are incorrectly treated as unsigned, leading to memory corruption scenarios.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable more sophisticated attacks. Remote attackers can leverage this flaw to cause application crashes through carefully constructed PDF documents, effectively creating a reliable denial of service vector. In certain scenarios, the buffer over-read may expose sensitive memory contents or allow for information disclosure, though the exact scope of potential impacts remains unspecified in the vulnerability description. This makes the vulnerability particularly dangerous in environments where PDF processing is automated or where users may encounter untrusted documents, such as email systems, web applications, or document management platforms that utilize Poppler for PDF handling.
Mitigation strategies for CVE-2019-7310 primarily involve immediate software updates to versions that have addressed the integer signedness error in the XRef::getEntry function. System administrators should prioritize patching affected Poppler installations and ensuring that all applications relying on the library are updated accordingly. Additionally, implementing proper input validation and sanitization measures can help reduce the attack surface, particularly in environments where processing untrusted PDF content is unavoidable. Organizations should also consider deploying defensive measures such as PDF sandboxing, content filtering, and restricted execution environments to limit the potential impact of exploitation attempts. The vulnerability highlights the importance of rigorous code review processes and automated testing for integer handling, particularly in security-critical components that process untrusted data, aligning with ATT&CK technique T1059.007 for application layer execution and T1499.004 for network denial of service through application-level attacks.