CVE-2015-2424

What Is Microsoft PowerPoint?

Microsoft PowerPoint is the world's dominant presentation software, used across enterprise, government, academia, and consumer environments. PowerPoint presentation files (.ppt, .pptx, .pps, .ppsx) support embedded objects, custom fonts, VBA macros, and linked media — creating a complex parsing attack surface. Like Word and Excel, PowerPoint's document parser processes attacker-controlled binary or XML data, making memory corruption vulnerabilities in PowerPoint a reliable vehicle for targeted attacks via malicious email attachments.

Overview

CVE-2015-2424 is a memory corruption vulnerability in Microsoft PowerPoint that allows remote code execution when a user opens a specially crafted Office presentation file. The vulnerability was actively exploited in targeted spear-phishing attacks against specific organizations and individuals. Patched in MS15-070 (July 14, 2015), which addressed multiple Office memory corruption vulnerabilities.

Affected Versions

Fixed with MS15-070 (July 2015).

Technical Details

Root Cause: Memory Corruption in Presentation File Parsing

CVE-2015-2424 involves an out-of-bounds write or related memory corruption (CWE-787) in PowerPoint's processing of presentation file structures. The PowerPoint parser allocates a buffer for specific slide or object data, but a malformed or crafted file element causes data to be written beyond the allocated bounds — corrupting adjacent heap memory.

With precise heap grooming (achievable through careful document construction), the corruption can be directed to overwrite a function pointer or vtable in an adjacent PowerPoint internal object — causing that pointer to be invoked at an attacker-chosen address when PowerPoint performs subsequent operations on the object.

Attack Delivery

Standard PowerPoint exploit delivery:

1. Attacker constructs a malicious PowerPoint file (.ppt, .pptx, or .pps)
2. File is sent as an email attachment in a targeted spear-phishing campaign
3. Recipient opens the file in Microsoft PowerPoint
4. PowerPoint's parser processes the malicious structure, triggering the overflow
5. Code execution at the user's privilege level

Attack Characteristics

Discovery

Reported to Microsoft and patched in MS15-070 (July 2015 Patch Tuesday), which addressed multiple memory corruption vulnerabilities in Microsoft Office components including Word, Excel, and PowerPoint.

Exploitation Context

• APT spear-phishing: Malicious PowerPoint files are a standard APT delivery mechanism; CVE-2015-2424 was exploited in targeted attacks where presentation files were sent to specific individuals in government, defense, and financial sectors
• File format trust: PowerPoint files are routinely exchanged in business settings and often pass through email security filters that target executable files — making PPT/PPTX attachments an effective malware delivery vehicle
• Long exploitation tail: CISA KEV addition in March 2022 — nearly seven years after patch — confirms continued exploitation of CVE-2015-2424 against organizations with outdated Office installations
• CISA KEV (2022): Added March 2022

Remediation

1. Apply MS15-070 (July 2015). Any Office installation updated after July 2015 includes this fix.

2. Enable Office Protected View — opens externally received documents in a sandboxed read-only mode, preventing automatic exploitation when a file is opened.

3. Maintain current Office updates — monthly security updates from Microsoft address Office parser vulnerabilities; current patch levels eliminate this vulnerability.

4. Email attachment scanning — configure email gateways to scan Office attachments for known exploit signatures and sandbox suspicious files before delivery.

5. Deploy ASR rules — Attack Surface Reduction rules can block Office from creating child processes, limiting post-exploitation impact.