CVE-2019-5772 in Chrome
Summary
by MITRE
Sharing of objects over calls into JavaScript runtime in PDFium in Google Chrome prior to 72.0.3626.81 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.
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Analysis
by VulDB Data Team • 07/11/2023
The vulnerability identified as CVE-2019-5772 represents a critical heap corruption issue within the PDFium library component of Google Chrome browser. This flaw exists in versions prior to 72.0.3626.81 and specifically affects how the JavaScript runtime handles object sharing across function calls when processing PDF documents. The vulnerability stems from improper memory management during the execution of JavaScript code embedded within PDF files, creating opportunities for malicious actors to manipulate heap memory structures through carefully crafted PDF content.
The technical implementation of this vulnerability involves the improper handling of object references within the PDFium rendering engine's JavaScript interpreter. When Chrome processes PDF documents containing malicious JavaScript code, the runtime fails to properly validate object sharing across different call contexts, leading to memory corruption that can be exploited to execute arbitrary code. This heap corruption occurs due to insufficient bounds checking and memory management controls during JavaScript object lifecycle operations within the PDF processing pipeline. The flaw is classified under CWE-122 as "Heap-based Buffer Overflow" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" as it leverages JavaScript execution capabilities for exploitation.
The operational impact of CVE-2019-5772 extends beyond simple privilege escalation scenarios, as it enables remote code execution capabilities that can be weaponized through web-based attacks. Attackers can craft malicious PDF files that, when opened in vulnerable Chrome versions, trigger the heap corruption exploit, potentially allowing full system compromise. The vulnerability's remote exploitability means that users can be targeted simply by visiting compromised websites or opening malicious attachments, making it particularly dangerous in enterprise environments where users frequently interact with untrusted PDF content. This vulnerability specifically affects the browser's security model by undermining the sandboxing mechanisms that normally isolate PDF processing from the underlying operating system.
Mitigation strategies for CVE-2019-5772 primarily focus on immediate browser updates to versions 72.0.3626.81 or later, where Google has implemented fixes for the heap corruption issue. Organizations should also consider implementing additional security measures such as PDF file scanning, browser hardening configurations, and network-level protections to reduce the attack surface. The fix addresses the underlying memory management issues in PDFium's JavaScript runtime by introducing proper object reference validation and heap boundary checking during cross-call object sharing operations. Security teams should also monitor for any related vulnerabilities in the PDFium library and maintain updated threat intelligence on exploitation attempts targeting this specific flaw.