CVE-2025-30410: Acronis Cyber Protect Auth Bypass Flaw

CVE-2025-30410 Overview

CVE-2025-30410 is a critical authentication bypass vulnerability affecting multiple Acronis Cyber Protect products. The vulnerability stems from missing authentication controls (CWE-306), allowing unauthenticated attackers to access and manipulate sensitive data across affected systems. This flaw enables network-based attackers to bypass security controls without any user interaction or special privileges, potentially compromising the confidentiality and integrity of protected backup and recovery data.

Critical Impact

Unauthenticated attackers can remotely access and manipulate sensitive data in Acronis Cyber Protect environments, potentially compromising backup integrity and exposing confidential information across enterprise deployments.

Affected Products

• Acronis Cyber Protect Cloud Agent (Linux, macOS, Windows) before build 39870
• Acronis Cyber Protect 16 (Linux, macOS, Windows) before build 39938
• Acronis Cyber Protect 15 (Linux, macOS, Windows) before build 41800

Discovery Timeline

• 2026-02-20 - CVE-2025-30410 published to NVD
• 2026-02-20 - Last updated in NVD database

Technical Details for CVE-2025-30410

Vulnerability Analysis

This vulnerability represents a severe authentication bypass condition classified under CWE-306 (Missing Authentication for Critical Function). The flaw exists in Acronis Cyber Protect products where certain critical functions lack proper authentication verification, allowing unauthenticated remote attackers to access functionality that should require authentication.

The vulnerability enables complete compromise of confidentiality, integrity, and availability of affected systems. Attackers can exploit this weakness to access sensitive backup data, modify protection configurations, or manipulate recovery operations without providing valid credentials.

Root Cause

The root cause is the absence of authentication checks on critical API endpoints or services within the Acronis Cyber Protect application. Functions that handle sensitive data operations fail to verify that the requesting entity has been properly authenticated before processing requests, violating fundamental security principles of defense in depth.

Attack Vector

The attack can be executed remotely over the network without requiring any user interaction or prior authentication. An attacker with network access to the vulnerable Acronis Cyber Protect services can directly interact with unprotected endpoints to:

1. Access sensitive backup configuration data and credentials
2. Retrieve protected backup contents without authorization
3. Modify backup schedules and protection policies
4. Manipulate or delete existing backup data

The exploitation requires no special privileges, making this vulnerability particularly dangerous in environments where Acronis services are exposed to untrusted networks.

Detection Methods for CVE-2025-30410

Indicators of Compromise

• Unexpected access to Acronis Cyber Protect management interfaces from unauthorized IP addresses
• Anomalous API requests to Acronis services without corresponding authentication events
• Unauthorized modifications to backup policies or protection configurations
• Suspicious data exfiltration patterns from backup storage locations

Detection Strategies

• Monitor network traffic for unauthenticated requests to Acronis Cyber Protect service ports
• Implement alerting for access attempts to sensitive Acronis endpoints without valid session tokens
• Review Acronis application logs for access patterns that bypass normal authentication flows
• Deploy network-based intrusion detection rules to identify exploitation attempts

Monitoring Recommendations

• Enable comprehensive audit logging on all Acronis Cyber Protect components
• Configure SIEM correlation rules to detect authentication bypass patterns
• Monitor for unusual backup data access or configuration changes outside maintenance windows
• Implement network segmentation monitoring to detect lateral movement following compromise

How to Mitigate CVE-2025-30410

Immediate Actions Required

• Update Acronis Cyber Protect Cloud Agent to build 39870 or later immediately
• Update Acronis Cyber Protect 16 to build 39938 or later
• Update Acronis Cyber Protect 15 to build 41800 or later
• Restrict network access to Acronis services to trusted management networks only

Patch Information

Acronis has released security updates addressing this vulnerability. Organizations should apply the following minimum build versions:

For complete details, refer to the Acronis Security Advisory SEC-8641.

Workarounds

• Implement strict network segmentation to isolate Acronis Cyber Protect services from untrusted networks
• Deploy a web application firewall or reverse proxy requiring authentication before reaching Acronis services
• Use host-based firewalls to restrict access to Acronis service ports to authorized management systems only
• Consider temporarily disabling external network access to affected Acronis services until patches can be applied

# Example: Restrict network access to Acronis services using iptables (Linux)
# Only allow connections from trusted management subnet
iptables -A INPUT -p tcp --dport 9876 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 9876 -j DROP

# Example: Windows Firewall restriction
netsh advfirewall firewall add rule name="Restrict Acronis Access" dir=in action=allow protocol=tcp localport=9876 remoteip=10.0.0.0/24
netsh advfirewall firewall add rule name="Block Acronis External" dir=in action=block protocol=tcp localport=9876