CVE-2015-6691 in Acrobat Reader
Summary
by MITRE
Use-after-free vulnerability in Adobe Reader and Acrobat 10.x before 10.1.16 and 11.x before 11.0.13, Acrobat and Acrobat Reader DC Classic before 2015.006.30094, and Acrobat and Acrobat Reader DC Continuous before 2015.009.20069 on Windows and OS X allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2015-5586, CVE-2015-6683, CVE-2015-6684, CVE-2015-6687, CVE-2015-6688, CVE-2015-6689, CVE-2015-6690, CVE-2015-7615, CVE-2015-7617, and CVE-2015-7621.
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Analysis
by VulDB Data Team • 06/21/2022
This vulnerability represents a critical use-after-free flaw in Adobe Acrobat and Reader products that affects multiple versions across different platforms. The issue stems from improper memory management where freed memory blocks are still referenced by subsequent operations, creating potential exploitation opportunities for malicious actors. The vulnerability impacts Adobe Reader versions 10.x before 10.1.16 and 11.x before 11.0.13, along with Acrobat and Acrobat Reader DC Classic and Continuous versions prior to their respective patches. This particular weakness is classified under CWE-416 as a use-after-free condition, which is a well-known class of memory safety vulnerabilities that frequently leads to arbitrary code execution. The vulnerability operates through unspecified attack vectors that distinguish it from several other related vulnerabilities in the same timeframe, making it particularly challenging to detect and mitigate without specific patching.
The technical exploitation of this use-after-free vulnerability allows attackers to achieve arbitrary code execution on affected systems, representing a severe privilege escalation risk. When the vulnerable application processes maliciously crafted PDF files, the improper memory handling can lead to heap corruption that attackers can manipulate to inject and execute malicious code with the privileges of the targeted user. This type of vulnerability is particularly dangerous in enterprise environments where users frequently open PDF documents from untrusted sources. The attack typically involves crafting a PDF file that triggers the memory management error during document parsing, causing the application to reference freed memory locations. The exploitation process often requires precise control over memory layout and can leverage techniques such as heap spraying or return-oriented programming to achieve reliable code execution. This vulnerability falls under the ATT&CK technique T1059 for command and scripting interpreter, as successful exploitation can lead to full system compromise and persistence mechanisms.
The operational impact of this vulnerability extends beyond immediate exploitation to encompass broader security implications for organizations relying on Adobe Acrobat products. Organizations using affected versions face significant risk of data breaches, system compromise, and potential lateral movement within their networks. The vulnerability's presence in both desktop and mobile versions of Adobe products means that security teams must implement comprehensive patch management strategies across their entire infrastructure. The affected products include not just traditional desktop applications but also the newer DC Classic and Continuous versions, indicating that the memory management flaw persists across different product lines and release cycles. Security teams must consider the vulnerability's impact on user productivity, as exploitation could result in complete system compromise requiring extensive forensic analysis and recovery procedures. The presence of this vulnerability in Adobe's widely deployed products creates an elevated risk profile that requires immediate attention and remediation efforts to prevent successful exploitation attempts.
Mitigation strategies for this vulnerability primarily focus on immediate patch deployment and application of Adobe's security updates. Organizations should prioritize updating to Adobe Reader 10.1.16, 11.0.13, or the appropriate DC versions that contain the necessary fixes for this use-after-free condition. The patching process should include comprehensive testing in controlled environments before full deployment to ensure compatibility with existing business applications and workflows. Additional defensive measures include implementing strict PDF file handling policies, such as disabling JavaScript execution in Acrobat Reader, restricting PDF file access to trusted sources, and deploying sandboxing solutions to isolate PDF processing operations. Network-based controls can include content filtering solutions that scan PDF files for known malicious patterns or suspicious structures that might trigger the vulnerability. Security monitoring should focus on detecting unusual PDF processing activities, memory allocation patterns, and potential exploitation attempts through network traffic analysis. The vulnerability's classification as a use-after-free makes it particularly susceptible to exploitation through social engineering campaigns targeting users to open malicious PDF attachments, emphasizing the need for comprehensive security awareness training programs. Organizations should also consider implementing application whitelisting policies to restrict execution of untrusted PDF processing applications and maintain detailed audit logs to track PDF file handling activities for forensic analysis purposes.