CVE-2015-6686 in Acrobat Reader
Summary
by MITRE
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 allow attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted set of fields, a different vulnerability than CVE-2015-6685, CVE-2015-6693, CVE-2015-6694, CVE-2015-6695, and CVE-2015-7622.
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Analysis
by VulDB Data Team • 06/21/2022
This vulnerability resides within Adobe Reader and Acrobat software products, specifically affecting versions prior to 10.1.16 and 11.0.13 for the classic editions, as well as older versions of the DC Classic and DC Continuous variants. The flaw manifests through a carefully crafted set of fields within PDF documents that can trigger memory corruption conditions when processed by the affected software. Unlike other related vulnerabilities such as CVE-2015-6685, CVE-2015-6693, CVE-2015-6694, CVE-2015-6695, and CVE-2015-7622, this particular vulnerability represents a distinct code path that exploits field processing mechanisms within the PDF rendering engine. The vulnerability is classified under the Common Weakness Enumeration category CWE-125, which describes out-of-bounds read conditions, and may also relate to CWE-787, representing out-of-bounds write conditions, depending on the specific memory corruption vector exploited. The attack surface is particularly concerning as it allows for arbitrary code execution when a user opens a maliciously crafted PDF document, or it can cause denial of service through memory corruption that crashes the application. The vulnerability affects both Windows and macOS operating systems, indicating a cross-platform threat vector that increases the potential impact across different environments.
The technical exploitation of this vulnerability occurs when the PDF processing engine encounters malformed or specially constructed field elements within a PDF document. These fields are processed in a manner that leads to improper memory handling, causing either buffer overflows or heap corruption that can be leveraged by attackers to execute arbitrary code with the privileges of the user running the affected software. The memory corruption typically occurs during the parsing and rendering of PDF fields, where input validation is insufficient to handle malformed data structures. Attackers can craft PDF documents containing these malicious field constructs, which when opened by an unpatched version of Adobe Reader or Acrobat, trigger the memory corruption vulnerability. The exploitation requires no special privileges beyond the ability to deliver a malicious PDF document to a target user, making this particularly dangerous in phishing campaigns or targeted attacks. The vulnerability's classification under ATT&CK technique T1203, which covers Exploitation for Client Execution, indicates that this vulnerability is commonly used in attack chains where adversaries seek to execute code on a victim's machine through document-based attacks.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as successful exploitation can result in complete system compromise. When an attacker successfully executes arbitrary code through this vulnerability, they can gain full control over the victim's system, potentially leading to data exfiltration, persistence mechanisms, or further network exploration. The vulnerability affects enterprise environments where PDF documents are commonly shared and opened, making it a prime target for advanced persistent threat actors and cybercriminals. Organizations running unpatched versions of Adobe Reader or Acrobat are particularly vulnerable, as these applications are widely deployed across different business sectors. The memory corruption nature of the vulnerability means that the effects can be unpredictable, potentially leading to system instability or crashes, which may also be leveraged in denial of service attacks against critical infrastructure. Security teams should be particularly vigilant about monitoring for this vulnerability in environments where PDF processing is common, as it can be easily exploited through social engineering campaigns that distribute malicious PDF documents through email or other communication channels. The vulnerability's impact is amplified by the fact that Adobe Reader and Acrobat are frequently used applications in business environments, increasing the probability of successful exploitation and making it a high-priority vulnerability for remediation across enterprise networks.