CVE-2011-0656 in PowerPoint
Summary
by MITRE
Microsoft PowerPoint 2002 SP3, 2003 SP3, 2007 SP2, and 2010; Office 2004, 2008, and 2011 for Mac; Open XML File Format Converter for Mac; Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP2; PowerPoint Viewer; PowerPoint Viewer 2007 SP2; and PowerPoint Web App do not properly validate PersistDirectoryEntry records in PowerPoint documents, which allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a Slide with a malformed record, which triggers an exception and later use of an unspecified method, aka "Persist Directory RCE Vulnerability."
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Analysis
by VulDB Data Team • 01/06/2025
The CVE-2011-0656 vulnerability represents a critical remote code execution flaw affecting multiple versions of Microsoft PowerPoint and related Office applications across different platforms. This vulnerability specifically targets the improper validation of PersistDirectoryEntry records within PowerPoint document structures, creating a pathway for malicious actors to exploit memory corruption issues through carefully crafted slide presentations. The flaw exists in the way these applications process and validate directory entries during document parsing, particularly when handling malformed PersistDirectoryEntry records that are part of the PowerPoint file format's internal structure.
The technical implementation of this vulnerability stems from insufficient input validation mechanisms within the PowerPoint parsing engine. When a maliciously crafted PowerPoint file contains a Slide with a malformed PersistDirectoryEntry record, the application's document parser fails to properly validate the record structure before processing it. This validation failure results in an exception being thrown during the parsing phase, but the subsequent handling of this exception leads to memory corruption conditions that can be leveraged by attackers. The vulnerability manifests as an unspecified method being called after the exception handling, creating opportunities for arbitrary code execution or denial of service conditions. This type of vulnerability aligns with CWE-129, which covers improper validation of input boundaries, and CWE-787, which addresses out-of-bounds write operations.
The operational impact of CVE-2011-0656 extends across multiple Microsoft Office product lines including Windows and Mac versions of PowerPoint, Office Compatibility Pack, and various PowerPoint Viewer applications. Attackers can exploit this vulnerability by crafting malicious PowerPoint files that appear legitimate but contain the malformed PersistDirectoryEntry records designed to trigger the memory corruption. The remote execution aspect means that simply opening a malicious presentation file could lead to compromise, making this particularly dangerous in phishing campaigns or targeted attacks. The vulnerability affects not only end-user systems but also enterprise environments where PowerPoint documents are frequently shared and opened across different platforms and Office versions.
Organizations should implement immediate mitigations including applying Microsoft security patches and updates, deploying application whitelisting policies to restrict execution of PowerPoint files from untrusted sources, and implementing email filtering solutions that can detect and block suspicious PowerPoint attachments. Network segmentation and monitoring should be enhanced to detect potential exploitation attempts. The ATT&CK framework categorizes this vulnerability under T1203, which covers Exploitation for Client Execution, and T1059, covering Command and Scripting Interpreter, as attackers may leverage this vulnerability to execute arbitrary commands. Additionally, implementing proper file validation and content inspection mechanisms at network perimeters can help prevent exploitation of this vulnerability in transit. Regular security awareness training for users should emphasize the dangers of opening PowerPoint files from unknown sources, as social engineering remains a primary attack vector for this type of vulnerability.