CVE-2022-35672 in Acrobat Reader
Summary
by MITRE • 07/27/2022
Adobe Acrobat Reader version 22.001.20085 (and earlier), 20.005.30314 (and earlier) and 17.012.30205 (and earlier) are affected by an out-of-bounds read vulnerability when parsing a crafted file, which could result in a read past the end of an allocated memory structure. An attacker could leverage this vulnerability to execute code in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.
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Analysis
by VulDB Data Team • 07/27/2022
This vulnerability resides in Adobe Acrobat Reader's document parsing engine where an out-of-bounds read condition occurs when processing specially crafted PDF files. The flaw manifests in the memory management routines responsible for handling document structures, specifically when the application attempts to read data beyond the boundaries of allocated memory buffers. The vulnerability affects multiple versions including 22.001.20085 and earlier, 20.005.30314 and earlier, as well as 17.012.30205 and earlier releases, indicating a persistent issue across the product's lifecycle. The root cause stems from inadequate bounds checking within the PDF parsing logic, where the application fails to properly validate array indices or buffer sizes before accessing memory locations. This type of vulnerability falls under CWE-129 which specifically addresses insufficient validation of length of input buffers, and more broadly aligns with CWE-125 which covers out-of-bounds read conditions. The security implications are severe as this vulnerability can be exploited through social engineering techniques where an attacker crafts a malicious PDF file designed to trigger the memory access error during normal document rendering operations. When a victim opens the crafted file, the application's parsing routine executes an out-of-bounds memory read that can be manipulated to overwrite critical memory regions or redirect execution flow. The attack requires user interaction as the victim must open the malicious file, making this a classic sandbox escape vector that leverages the trust users place in document viewing applications. From an operational perspective, this vulnerability presents a significant risk to enterprise environments where PDF documents are frequently shared and opened by multiple users, creating numerous potential attack vectors. The exploitability factor is enhanced by the fact that PDF files are commonly used in business communications, making it easier for attackers to craft convincing phishing campaigns. The execution context remains limited to the current user's privileges, but the potential for privilege escalation exists through chained attacks or exploitation of additional vulnerabilities in the system. This vulnerability maps to several ATT&CK techniques including initial access through spearphishing attachments, execution through legitimate system binaries, and privilege escalation through memory corruption exploits. The memory corruption aspect of this vulnerability aligns with ATT&CK T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation. Organizations should prioritize patching affected versions as the vulnerability enables remote code execution capabilities that could lead to full system compromise. The fix typically involves implementing proper bounds checking mechanisms and validating all array access operations within the PDF parsing components. Security teams should also consider network-based detection measures to identify potentially malicious PDF files and implement user awareness training to reduce successful exploitation attempts. The vulnerability demonstrates the critical importance of input validation in document processing applications and highlights how seemingly benign file operations can become attack vectors when proper security controls are absent.