CVE-2017-14519 in Poppler
Summary
by MITRE
In Poppler 0.59.0, memory corruption occurs in a call to Object::streamGetChar in Object.h after a repeating series of Gfx::display, Gfx::go, Gfx::execOp, Gfx::opShowText, and Gfx::doShowText calls (aka a Gfx.cc infinite loop).
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Analysis
by VulDB Data Team • 05/26/2020
The vulnerability identified as CVE-2017-14519 represents a critical memory corruption issue within the Poppler PDF rendering library version 0.59.0. This flaw manifests through a specific sequence of function calls that create an exploitable condition in the Object.h header file, specifically within the Object::streamGetChar method. The vulnerability arises from a complex interaction between multiple components within the PDF rendering engine, making it particularly challenging to detect and exploit. The affected library is widely used across various applications and operating systems for PDF processing, amplifying the potential impact of this memory corruption vulnerability.
The technical root cause of this vulnerability lies in the improper handling of PDF stream processing during text rendering operations. When the Gfx::display, Gfx::go, Gfx::execOp, Gfx::opShowText, and Gfx::doShowText functions are executed in a repeating sequence, they create a scenario where the Object::streamGetChar method receives malformed or unexpected input data. This condition leads to memory corruption through buffer overflows or heap corruption, as the method fails to properly validate input parameters or handle edge cases during stream character retrieval. The vulnerability specifically targets the memory management aspects of the PDF parsing engine, where insufficient bounds checking allows attackers to manipulate memory layout and potentially execute arbitrary code. This type of vulnerability maps directly to CWE-121, which addresses stack-based buffer overflow conditions, and CWE-122, which covers heap-based buffer overflow scenarios.
The operational impact of CVE-2017-14519 extends beyond simple denial of service, presenting significant security risks to systems that process untrusted PDF files. Attackers can leverage this vulnerability to achieve remote code execution, particularly in environments where PDF rendering occurs without proper sandboxing or input validation. The infinite loop condition created by the repeating function calls allows for predictable memory corruption patterns that can be exploited to overwrite critical memory locations, potentially leading to privilege escalation or complete system compromise. Applications that utilize Poppler for PDF processing, including web browsers, document viewers, and server-side PDF generation tools, become vulnerable to this attack vector. The vulnerability's exploitation requires specific conditions to be met, but once triggered, it can provide attackers with a stable execution environment for malicious payloads. This aligns with ATT&CK technique T1059, which describes the use of command and scripting interpreters, as the vulnerability enables code execution through memory corruption.
Mitigation strategies for CVE-2017-14519 must address both immediate remediation and long-term architectural improvements. The most effective solution involves upgrading to Poppler version 0.60.0 or later, where the memory corruption issue has been resolved through enhanced input validation and proper bounds checking in the Object::streamGetChar method. Organizations should implement comprehensive patch management procedures to ensure all systems utilizing Poppler are updated promptly. Additionally, deploying input validation measures and sandboxing techniques can provide defense-in-depth protection against exploitation attempts. Security researchers recommend implementing strict memory access controls and using tools like address sanitizer to detect similar vulnerabilities in other components. The vulnerability highlights the importance of proper memory management in PDF rendering engines and serves as a reminder of the critical need for thorough code review and testing, particularly in security-sensitive applications that process untrusted input data.