CVE-2023-46216: Ivanti Avalanche DoS Vulnerability

CVE-2023-46216 Overview

CVE-2023-46216 is a critical memory corruption vulnerability affecting Ivanti Avalanche Mobile Device Server. An attacker sending specially crafted data packets to the Mobile Device Server can cause memory corruption which could result in a Denial of Service (DoS) or remote code execution. This vulnerability is classified as CWE-787 (Out-of-Bounds Write), indicating that the application writes data past the boundaries of allocated memory buffers.

Critical Impact

This vulnerability allows unauthenticated remote attackers to potentially execute arbitrary code or crash the Mobile Device Server through specially crafted network packets, compromising enterprise mobile device management infrastructure.

Affected Products

• Ivanti Avalanche (on-premise versions prior to 6.4.2)
• Microsoft Windows (as the host operating system)
• Ivanti Avalanche Mobile Device Server component

Discovery Timeline

• 2023-12-19 - CVE-2023-46216 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-46216

Vulnerability Analysis

This vulnerability exists within the Mobile Device Server component of Ivanti Avalanche, an enterprise mobility management solution used to deploy, manage, and secure mobile devices across organizations. The flaw stems from improper handling of incoming network data packets, leading to an out-of-bounds write condition (CWE-787).

When the Mobile Device Server processes specially crafted data packets, insufficient bounds checking allows an attacker to write data beyond the intended memory buffer boundaries. This memory corruption can be leveraged in two primary ways: causing the service to crash (Denial of Service) or, in more sophisticated attacks, achieving arbitrary code execution on the underlying system.

The vulnerability is particularly concerning because it requires no authentication and can be exploited remotely over the network. Organizations using Ivanti Avalanche to manage their mobile device fleet could face significant disruption if attackers target this vulnerability.

Root Cause

The root cause is an out-of-bounds write vulnerability (CWE-787) in the packet processing logic of the Mobile Device Server. The server fails to properly validate the size and boundaries of incoming data packets before writing them to memory buffers. This allows malicious input to overwrite adjacent memory regions, corrupting application state or control flow data structures.

Attack Vector

The attack is network-based and does not require authentication or user interaction. An attacker with network access to the Mobile Device Server port can send specially crafted packets designed to trigger the memory corruption condition.

The attack flow consists of:

1. The attacker identifies a network-accessible Ivanti Avalanche Mobile Device Server instance
2. Malicious data packets are crafted to exploit the bounds checking weakness
3. When processed by the server, these packets cause memory to be written outside intended buffer boundaries
4. Depending on the attacker's goal and exploitation technique, this results in either service disruption or code execution

Detection Methods for CVE-2023-46216

Indicators of Compromise

• Unexpected crashes or restarts of the Ivanti Avalanche Mobile Device Server service
• Anomalous network traffic patterns targeting Avalanche server ports
• Memory access violation errors in Windows Event Logs associated with Avalanche processes
• Unusual process behavior or child processes spawned from Avalanche services

Detection Strategies

• Deploy network intrusion detection rules to identify malformed packets targeting Avalanche services
• Monitor Avalanche service processes for unexpected termination or restart patterns
• Implement endpoint detection for memory corruption exploitation techniques on servers hosting Avalanche
• Review application and system logs for signs of exploitation attempts

Monitoring Recommendations

• Enable verbose logging for Ivanti Avalanche Mobile Device Server components
• Configure alerting for service availability monitoring to detect DoS conditions
• Deploy network traffic analysis to baseline normal Avalanche communication patterns and detect anomalies
• Monitor for unauthorized network connections to Avalanche server ports from untrusted sources

How to Mitigate CVE-2023-46216

Immediate Actions Required

• Upgrade Ivanti Avalanche to version 6.4.2 or later immediately
• Restrict network access to the Mobile Device Server to only trusted management networks
• Implement network segmentation to isolate Avalanche infrastructure from untrusted network segments
• Enable enhanced monitoring and logging on affected systems until patching is complete

Patch Information

Ivanti has addressed this vulnerability in Avalanche version 6.4.2. Organizations should review the Ivanti Avalanche 6.4.2 Release Notes for complete details on the security fixes included in this release. The update should be applied to all on-premise Ivanti Avalanche installations as a priority.

Workarounds

• Implement strict firewall rules to limit access to the Mobile Device Server from trusted IP addresses only
• Deploy a web application firewall or network security appliance capable of deep packet inspection in front of Avalanche services
• Consider temporarily disabling the Mobile Device Server component if not critical to operations until patching can be completed
• Enable network-level authentication where possible to add an additional barrier to exploitation

# Example: Restrict access to Avalanche server using Windows Firewall
# Replace AVALANCHE_PORT with the actual port number and TRUSTED_NETWORK with your management subnet

netsh advfirewall firewall add rule name="Restrict Avalanche Access" ^
    dir=in action=allow protocol=tcp localport=AVALANCHE_PORT ^
    remoteip=TRUSTED_NETWORK/24

netsh advfirewall firewall add rule name="Block Avalanche Public" ^
    dir=in action=block protocol=tcp localport=AVALANCHE_PORT