CVE-2021-43015
📋 TL;DR
This vulnerability allows attackers to execute arbitrary code on systems running vulnerable versions of Adobe InCopy by tricking users into opening malicious GIF files. The vulnerability affects Adobe InCopy 16.4 and earlier versions, putting users who open untrusted files at risk of complete system compromise.
💻 Affected Systems
- Adobe InCopy
📦 What is this software?
Incopy by Adobe
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the current user, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malware installation or data exfiltration when users open malicious GIF files from untrusted sources.
If Mitigated
Limited impact if users only open trusted files and have proper endpoint protection.
🎯 Exploit Status
Requires user interaction (opening malicious file) but memory corruption vulnerabilities can be reliably exploited.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 16.4.1 and later
Vendor Advisory: https://helpx.adobe.com/security/products/incopy/apsb21-110.html
Restart Required: Yes
Instructions:
1. Open Adobe InCopy. 2. Go to Help > Check for Updates. 3. Follow prompts to install version 16.4.1 or later. 4. Restart the application.
🔧 Temporary Workarounds
Disable GIF file association
allPrevent InCopy from automatically opening GIF files by changing file associations.
Windows: Control Panel > Default Programs > Associate a file type or protocol with a program
macOS: Right-click GIF file > Get Info > Open With > Change
Application sandboxing
allRun InCopy in a sandboxed environment to limit potential damage.
Windows: Use Windows Sandbox or third-party sandboxing tools
macOS: Use built-in sandboxing features or third-party tools
🧯 If You Can't Patch
- Implement strict file handling policies: Block GIF files from untrusted sources and educate users about risks.
- Deploy endpoint protection: Use antivirus/EDR solutions that can detect and block malicious GIF files.
🔍 How to Verify
Check if Vulnerable:
Check InCopy version: Open InCopy > Help > About Adobe InCopy. If version is 16.4 or earlier, system is vulnerable.Check Version:
Windows: wmic product where name="Adobe InCopy" get version
macOS: /Applications/Adobe\ InCopy\ */Adobe\ InCopy.app/Contents/Info.plist | grep -A1 CFBundleShortVersionStringVerify Fix Applied:
Verify version is 16.4.1 or later in Help > About Adobe InCopy.📡 Detection & Monitoring
Log Indicators:
- Application crashes when opening GIF files
- Unusual process spawning from InCopy
- Memory access violations in application logs
Network Indicators:
- Outbound connections from InCopy to unknown IPs
- DNS requests for suspicious domains after file opening
SIEM Query:
source="*incopy*" AND (event_type="crash" OR process_name="*gif*")