CVE-2021-32581
📋 TL;DR
This vulnerability allows man-in-the-middle attackers to intercept and manipulate communications between Acronis products and their servers due to missing SSL certificate validation. Affected users include anyone running vulnerable versions of Acronis True Image for Windows/Mac, Acronis Agent, or Acronis Cyber Protect.
💻 Affected Systems
- Acronis True Image for Windows
- Acronis True Image for Mac
- Acronis Agent
- Acronis Cyber Protect
📦 What is this software?
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
True Image by Acronis
⚠️ Risk & Real-World Impact
Worst Case
Attackers could intercept backup data, inject malicious updates, steal credentials, or deploy ransomware through compromised updates.
Likely Case
Data interception during backup/restore operations, credential theft from authentication flows, or installation of malicious software updates.
If Mitigated
Limited impact if network segmentation prevents man-in-the-middle positioning or if using isolated backup environments.
🎯 Exploit Status
Exploitation requires man-in-the-middle positioning but is technically simple once positioned.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Acronis True Image 2021 Update 4 (Windows), 2021 Update 5 (Mac), Acronis Agent build 26653+, Acronis Cyber Protect build 27009+
Vendor Advisory: https://kb.acronis.com/content/68413
Restart Required: Yes
Instructions:
1. Open Acronis product. 2. Check for updates in settings. 3. Install available updates. 4. Restart the application or system as prompted.
🔧 Temporary Workarounds
Network segmentation
allIsolate Acronis systems from untrusted networks to prevent man-in-the-middle attacks.
Disable automatic updates
allTemporarily disable automatic updates and manually verify updates before installation.
🧯 If You Can't Patch
- Deploy network monitoring for SSL/TLS anomalies and unexpected certificate changes.
- Implement strict outbound firewall rules limiting Acronis traffic to known legitimate endpoints only.
🔍 How to Verify
Check if Vulnerable:
Check version in Acronis product settings against affected versions listed in advisory.Check Version:
Check Help > About in Acronis interface or consult system documentation for command-line version check.Verify Fix Applied:
Confirm version is updated to patched versions and test SSL certificate validation with controlled man-in-the-middle test.📡 Detection & Monitoring
Log Indicators:
- Failed SSL/TLS handshake logs, unexpected certificate warnings in application logs
Network Indicators:
- Unencrypted traffic to Acronis servers, SSL/TLS protocol anomalies, certificate validation failures
SIEM Query:
source="acronis" AND (event="ssl_error" OR event="certificate_validation_failed")