CVE-2024-45163: Mirai Botnet DoS Vulnerability

CVE-2024-45163 Overview

CVE-2024-45163 is a resource exhaustion vulnerability in the Mirai botnet's command and control (CNC) server that mishandles simultaneous TCP connections. The vulnerability allows unauthenticated sessions to remain open indefinitely, consuming server resources and potentially leading to denial of service conditions. An attacker can exploit this flaw by sending a recognized username (such as root) or arbitrary data to exhaust available resources on the CNC server.

Critical Impact

Attackers can remotely crash or disable Mirai botnet CNC servers by exploiting improper TCP connection handling, enabling disruption of botnet operations or potentially weaponizing this against botnet operators and their infrastructure.

Affected Products

• Mirai botnet CNC server (through 2024-08-19)
• Mirai botnet variants utilizing the vulnerable CNC server code
• Systems running unpatched Mirai CNC server implementations

Discovery Timeline

• 2024-08-22 - CVE-2024-45163 published to NVD
• 2024-08-22 - Last updated in NVD database

Technical Details for CVE-2024-45163

Vulnerability Analysis

This vulnerability stems from improper resource management (CWE-400) in the Mirai botnet's CNC server implementation. The server fails to properly terminate or timeout unauthenticated TCP connections, allowing them to persist and consume system resources. When an attacker establishes multiple simultaneous connections to the CNC server without completing authentication, these sessions remain open indefinitely. This design flaw enables resource exhaustion attacks where an attacker can overwhelm the server by maintaining numerous idle connections.

The vulnerability can be exploited remotely over the network without requiring any authentication or user interaction. The attack complexity is low, making it easily reproducible by attackers with basic knowledge of TCP connection handling. While the vulnerability does not compromise data confidentiality, it poses significant risks to both integrity and availability of affected systems.

Root Cause

The root cause is improper handling of TCP connection state management in the CNC server code. Specifically:

• The server does not implement proper connection timeouts for unauthenticated sessions
• No limit is enforced on the number of concurrent unauthenticated connections
• Sessions remain open when partial authentication data (like just a username) is sent
• Resource cleanup mechanisms fail to reclaim resources from stale connections

This represents a classic resource exhaustion vulnerability where the server allocates resources for incoming connections but lacks safeguards to release them when connections are not properly established or authenticated.

Attack Vector

The attack leverages the network-accessible nature of the CNC server to initiate multiple TCP connections. An attacker can exploit this vulnerability by:

1. Opening multiple TCP connections to the CNC server simultaneously
2. Sending partial authentication data such as a recognized username (e.g., root) or arbitrary data
3. Keeping these connections open without completing authentication
4. Repeating the process to exhaust server resources including memory, file descriptors, and CPU

The attack does not require any special privileges or authentication, making it accessible to any attacker who can reach the CNC server over the network. The vulnerability can be exploited to effectively disable botnet CNC infrastructure, which may be of interest to security researchers, law enforcement, or competing threat actors seeking to disrupt botnet operations.

For technical details on the exploitation mechanism, see the Remote DoS Exploit Analysis on Medium and the related security demonstration video.

Detection Methods for CVE-2024-45163

Indicators of Compromise

• Unusual spike in TCP connections to known Mirai CNC server ports
• Large number of half-open or established TCP connections from single or multiple source IPs
• Server resource exhaustion symptoms including high memory usage and file descriptor depletion
• CNC server becoming unresponsive or crashing unexpectedly

Detection Strategies

• Monitor for abnormal TCP connection patterns targeting port ranges typically used by Mirai CNC servers
• Implement network flow analysis to identify connection flooding behavior from external sources
• Deploy intrusion detection signatures for Mirai-related traffic patterns and partial authentication attempts
• Track server resource utilization metrics and alert on anomalous resource consumption

Monitoring Recommendations

• Enable connection tracking and logging on network boundary devices
• Configure alerts for rapid TCP connection establishment from single source IPs
• Monitor system resource metrics (memory, file descriptors, CPU) on systems potentially running CNC software
• Implement netflow or packet capture analysis for forensic investigation capabilities

How to Mitigate CVE-2024-45163

Immediate Actions Required

• Implement connection rate limiting on network devices to restrict connections per source IP
• Configure TCP connection timeouts to automatically close idle unauthenticated sessions
• Deploy firewall rules to limit access to CNC server ports from known trusted sources only
• Monitor and alert on resource exhaustion conditions to enable rapid incident response

Patch Information

As this vulnerability affects the Mirai botnet source code which is publicly available malware, there is no official vendor patch. Organizations defending against or researching Mirai should implement the mitigation strategies outlined below. Security researchers studying the vulnerability can reference the technical analysis available at the Pastebin Security Information for additional context.

Workarounds

• Implement strict connection timeouts at the network or application level to terminate idle sessions
• Deploy rate limiting to restrict the number of connections per source IP address
• Use firewall rules to whitelist only authorized IP addresses that should connect to CNC infrastructure
• Implement connection pooling with maximum limits to prevent resource exhaustion

# Configuration example - iptables rate limiting for connection flood mitigation
# Limit new TCP connections to 10 per minute per source IP
iptables -A INPUT -p tcp --syn -m connlimit --connlimit-above 10 -j DROP

# Set connection tracking timeout for established connections
sysctl -w net.netfilter.nf_conntrack_tcp_timeout_established=300

# Limit maximum tracked connections
sysctl -w net.netfilter.nf_conntrack_max=65536