CVE-2024-49388: Acronis Cyber Protect Auth Bypass Flaw

CVE-2024-49388 Overview

CVE-2024-49388 is a critical authorization bypass vulnerability affecting Acronis Cyber Protect 16 on Linux and Windows platforms. The vulnerability allows sensitive information manipulation due to improper authorization, enabling unauthenticated remote attackers to access and modify protected data without proper credentials. This flaw is classified as CWE-639 (Authorization Bypass Through User-Controlled Key), indicating that the application fails to properly validate user-supplied identifiers when authorizing access to sensitive resources.

Critical Impact

Unauthenticated remote attackers can manipulate sensitive information in Acronis Cyber Protect 16 environments, potentially compromising backup data integrity and confidentiality across enterprise deployments.

Affected Products

• Acronis Cyber Protect 16 (Linux) before build 38690
• Acronis Cyber Protect 16 (Windows) before build 38690
• Acronis Cyber Protect 16 Update 1 before build 38690

Discovery Timeline

• 2024-10-15 - CVE-2024-49388 published to NVD
• 2025-02-04 - Last updated in NVD database

Technical Details for CVE-2024-49388

Vulnerability Analysis

This authorization bypass vulnerability (CWE-639) allows attackers to manipulate sensitive information by exploiting improper authorization controls in the Acronis Cyber Protect application. The vulnerability is network-accessible without requiring authentication or user interaction, making it particularly dangerous in enterprise environments where Acronis Cyber Protect manages critical backup and recovery operations.

The flaw enables unauthorized modification and potential exfiltration of sensitive data managed by the backup solution. Given that Acronis Cyber Protect handles enterprise backup data, system configurations, and recovery information, successful exploitation could compromise the confidentiality and integrity of protected assets without affecting system availability.

Root Cause

The root cause is an improper authorization vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key). The application fails to properly verify that a user is authorized to access a specific resource when the resource identifier is supplied by the user. This allows attackers to bypass authorization controls by manipulating user-controlled parameters to access resources belonging to other users or protected system data.

Attack Vector

The attack vector is network-based, allowing remote unauthenticated attackers to exploit this vulnerability. The attacker can send specially crafted requests to the Acronis Cyber Protect service that bypass authorization checks, enabling access to and manipulation of sensitive information. The low attack complexity and lack of required privileges or user interaction make this vulnerability highly exploitable in exposed environments.

The vulnerability enables attackers to manipulate authorization parameters to gain unauthorized access to sensitive backup configurations, credentials, or protected data managed by the Acronis Cyber Protect platform. Successful exploitation could allow attackers to modify backup policies, access stored credentials, or tamper with backup data integrity.

Detection Methods for CVE-2024-49388

Indicators of Compromise

• Unexpected API requests to Acronis Cyber Protect services from unauthorized IP addresses
• Anomalous access patterns to backup configurations or protected resources
• Unauthorized modifications to backup policies or sensitive system settings
• Authentication log entries showing access to resources without proper authorization tokens

Detection Strategies

• Monitor Acronis Cyber Protect API access logs for requests that bypass normal authentication workflows
• Implement network-based detection for anomalous traffic patterns targeting Acronis services on default ports
• Review audit logs for unauthorized access to sensitive configuration endpoints
• Deploy behavioral analysis to detect unusual data access patterns within the backup infrastructure

Monitoring Recommendations

• Enable verbose logging on Acronis Cyber Protect servers to capture all API requests
• Implement SIEM rules to alert on unauthorized access attempts to backup management interfaces
• Monitor for changes to backup configurations or policies that were not initiated by authorized administrators
• Configure alerts for access to sensitive resources from unexpected network segments or IP ranges

How to Mitigate CVE-2024-49388

Immediate Actions Required

• Upgrade Acronis Cyber Protect 16 to build 38690 or later immediately
• Restrict network access to Acronis Cyber Protect management interfaces to trusted networks only
• Review audit logs for any signs of prior exploitation or unauthorized access
• Implement network segmentation to isolate backup infrastructure from general network access

Patch Information

Acronis has released build 38690 for Acronis Cyber Protect 16 that addresses this vulnerability. Organizations should apply this update immediately to all affected Linux and Windows installations. For detailed patch information, refer to the Acronis Security Advisory SEC-5984.

Workarounds

• Implement strict firewall rules to limit access to Acronis Cyber Protect services from trusted IP addresses only
• Deploy a web application firewall (WAF) in front of Acronis management interfaces to filter malicious requests
• Enable multi-factor authentication for all administrative access to the Acronis platform
• Consider temporarily disabling external access to management interfaces until patching is complete

# Example: Restrict access to Acronis Cyber Protect management port using iptables
iptables -A INPUT -p tcp --dport 9877 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 9877 -j DROP

# Example: Windows Firewall rule to restrict access
netsh advfirewall firewall add rule name="Acronis Management Restrict" dir=in action=allow protocol=tcp localport=9877 remoteip=10.0.0.0/8
netsh advfirewall firewall add rule name="Acronis Management Block" dir=in action=block protocol=tcp localport=9877