CVE-2023-36933: Progress MOVEit Transfer DoS Vulnerability

CVE-2023-36933 Overview

CVE-2023-36933 is a denial of service vulnerability affecting Progress MOVEit Transfer, a widely-used managed file transfer solution. The vulnerability allows an attacker to invoke a method that results in an unhandled exception, causing the MOVEit Transfer application to terminate unexpectedly. This improper handling of exceptional conditions (CWE-755) can be exploited remotely without authentication, potentially disrupting critical file transfer operations for organizations relying on this platform.

Critical Impact

Remote attackers can cause complete service disruption of MOVEit Transfer instances without requiring authentication, potentially halting enterprise file transfer operations.

Affected Products

• Progress MOVEit Transfer before 2021.0.9 (13.0.9)
• Progress MOVEit Transfer before 2021.1.7 (13.1.7)
• Progress MOVEit Transfer before 2022.0.7 (14.0.7)
• Progress MOVEit Transfer before 2022.1.8 (14.1.8)
• Progress MOVEit Transfer before 2023.0.4 (15.0.4)

Discovery Timeline

• July 5, 2023 - CVE-2023-36933 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-36933

Vulnerability Analysis

This vulnerability stems from improper exception handling within the MOVEit Transfer application. When certain methods are invoked through the application's network-accessible interface, the application fails to properly handle exceptional conditions, resulting in an unhandled exception that causes the entire service to crash. The vulnerability can be exploited remotely over the network with low attack complexity, requiring no privileges or user interaction.

The impact is focused entirely on availability—attackers cannot use this vulnerability to access confidential data or modify system integrity. However, the ability to repeatedly crash a critical file transfer service represents a significant operational risk, particularly for organizations that depend on MOVEit Transfer for time-sensitive business processes.

Root Cause

The root cause of CVE-2023-36933 is classified under CWE-755: Improper Handling of Exceptional Conditions. The application contains methods that can be invoked in ways that trigger exceptional conditions, but these conditions are not properly caught and handled. Instead of graceful error handling and recovery, the unhandled exception propagates through the application stack, resulting in process termination.

Attack Vector

The attack vector is network-based, meaning the vulnerability can be exploited remotely by any attacker who can reach the MOVEit Transfer service. The attack requires no authentication, no special privileges, and no user interaction. An attacker simply needs to identify the vulnerable method and craft requests that trigger the unhandled exception condition.

The vulnerability workflow involves:

1. Attacker identifies a network-accessible MOVEit Transfer instance
2. Attacker sends specially crafted requests to invoke the vulnerable method
3. The method encounters an exceptional condition that is not properly handled
4. The unhandled exception causes the application to terminate unexpectedly
5. Service becomes unavailable until manually restarted

Detection Methods for CVE-2023-36933

Indicators of Compromise

• Unexpected MOVEit Transfer service crashes or restarts in Windows Event logs
• Application crash dumps in the MOVEit Transfer logs directory
• Repeated service interruptions correlating with unusual network traffic patterns
• Unhandled exception entries in MOVEit Transfer application logs

Detection Strategies

• Monitor Windows Event logs for MOVEit Transfer service termination events (Event ID 7034 or 7031)
• Configure application crash monitoring to alert on unexpected process terminations
• Implement network-based anomaly detection for unusual request patterns to MOVEit endpoints
• Deploy SentinelOne Singularity platform to detect process crashes and suspicious activity patterns

Monitoring Recommendations

• Set up automated alerting for MOVEit Transfer service availability
• Implement uptime monitoring with rapid notification for service outages
• Configure log aggregation to correlate service crashes with incoming network requests
• Enable detailed application logging to capture exception details for forensic analysis

How to Mitigate CVE-2023-36933

Immediate Actions Required

• Identify all MOVEit Transfer instances in your environment and verify current version numbers
• Prioritize patching of internet-facing MOVEit Transfer deployments
• Apply the latest security patches from Progress as detailed in the vendor advisory
• Restrict network access to MOVEit Transfer services to authorized IP ranges where possible

Patch Information

Progress has released security patches addressing this vulnerability across all affected version branches. Organizations should update to the following minimum versions:

• Version 2021.0.9 (13.0.9) or later for the 2021.0.x branch
• Version 2021.1.7 (13.1.7) or later for the 2021.1.x branch
• Version 2022.0.7 (14.0.7) or later for the 2022.0.x branch
• Version 2022.1.8 (14.1.8) or later for the 2022.1.x branch
• Version 2023.0.4 (15.0.4) or later for the 2023.0.x branch

Detailed patch information is available in the Progress MOVEit Transfer Service Pack Advisory.

Workarounds

• Implement network segmentation to limit exposure of MOVEit Transfer services
• Deploy a web application firewall (WAF) to filter potentially malicious requests
• Configure automatic service restart policies to minimize downtime in case of crashes
• Establish enhanced monitoring to detect and respond to exploitation attempts rapidly

# Example: Configure Windows service recovery options for MOVEit Transfer
sc failure "MOVEit DMZ" reset= 86400 actions= restart/60000/restart/60000/restart/60000
# This configures the service to automatically restart after failures
# Note: This is a temporary mitigation only - patching is the recommended solution