CVE-2020-6115
📋 TL;DR
A use-after-free vulnerability in Nitro Pro PDF software allows attackers to execute arbitrary code by tricking victims into opening malicious PDF documents. This affects users of Nitro Pro 13.13.2.242 who open untrusted PDF files. Successful exploitation could lead to complete system compromise.
💻 Affected Systems
- Nitro Pro
📦 What is this software?
Nitro Pro by Gonitro
Nitro Pro by Gonitro
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with the privileges of the user running Nitro Pro, potentially leading to full system compromise, data theft, or ransomware deployment.
Likely Case
Arbitrary code execution leading to malware installation, credential theft, or lateral movement within the network.
If Mitigated
Limited impact if application runs with minimal privileges, sandboxing is enabled, and users avoid opening untrusted PDFs.
🎯 Exploit Status
Exploitation requires user interaction (opening a malicious PDF) but no authentication. Technical details and proof-of-concept are publicly available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 13.13.3.242 or later
Vendor Advisory: https://www.gonitro.com/nps/security/updates
Restart Required: Yes
Instructions:
1. Open Nitro Pro. 2. Go to Help > Check for Updates. 3. Follow prompts to install the latest version (13.13.3.242 or newer). 4. Restart the application.
🔧 Temporary Workarounds
Disable Nitro Pro as default PDF handler
windowsPrevent automatic opening of PDFs with Nitro Pro to reduce attack surface.
Control Panel > Default Programs > Set Default Programs > Select another PDF viewer
Use application sandboxing
windowsRun Nitro Pro in a sandboxed environment to limit potential damage from exploitation.
🧯 If You Can't Patch
- Restrict user permissions to run Nitro Pro with minimal privileges (non-admin accounts).
- Implement email/web filtering to block PDF attachments from untrusted sources.
🔍 How to Verify
Check if Vulnerable:
Check Nitro Pro version: Open Nitro Pro > Help > About. If version is exactly 13.13.2.242, the system is vulnerable.Check Version:
Not applicable for command line; use GUI method above.Verify Fix Applied:
Verify version is 13.13.3.242 or higher via Help > About in Nitro Pro.📡 Detection & Monitoring
Log Indicators:
- Unexpected application crashes of Nitro Pro
- Process creation from Nitro Pro with suspicious command lines
Network Indicators:
- Outbound connections from Nitro Pro to unexpected destinations
SIEM Query:
EventID=4688 AND ProcessName='NitroPDF.exe' AND CommandLine CONTAINS 'powershell' OR 'cmd'