CVE-2023-7340: Wazuh authd Buffer Overflow Vulnerability

CVE-2023-7340 Overview

CVE-2023-7340 is a heap-buffer overflow vulnerability (CWE-125: Out-of-Bounds Read) affecting the Wazuh authd authentication daemon. The vulnerability allows remote attackers to cause memory corruption and malformed heap data by sending specially crafted input to the service. When successfully exploited, this flaw enables attackers to trigger a denial of service condition, impacting the availability of the Wazuh authentication infrastructure.

Critical Impact

Remote attackers can crash the Wazuh authd daemon through heap-buffer overflow, disrupting authentication services and potentially leaving monitored endpoints unable to register or communicate with the Wazuh manager.

Affected Products

• Wazuh Wazuh (various versions)
• Wazuh version 4.3.10 and related releases

Discovery Timeline

• 2026-03-27 - CVE-2023-7340 published to NVD
• 2026-03-31 - Last updated in NVD database

Technical Details for CVE-2023-7340

Vulnerability Analysis

This heap-buffer overflow vulnerability exists within the Wazuh authd component, which is responsible for handling agent authentication and registration. The authd daemon processes incoming network requests from agents attempting to register with the Wazuh manager. When malformed or specially crafted input is received, the application fails to properly validate buffer boundaries before reading data, resulting in an out-of-bounds read condition (CWE-125).

The vulnerability is network-accessible and requires no prior authentication, making it exploitable by any attacker who can reach the authd service endpoint. While the impact is limited to availability rather than confidentiality or integrity, disruption of the authentication service can have cascading effects on security monitoring operations.

Root Cause

The root cause of CVE-2023-7340 is improper bounds checking when processing input data in the authd daemon. The service reads beyond allocated heap buffer boundaries when handling certain malformed requests, leading to out-of-bounds memory access. This failure to validate input length against buffer capacity is a classic memory safety issue that results in heap corruption.

Attack Vector

The attack vector for this vulnerability is network-based. An attacker can exploit CVE-2023-7340 by:

1. Identifying a Wazuh manager with the authd daemon exposed on the network
2. Crafting specially formatted input designed to trigger the buffer overflow condition
3. Sending the malicious payload to the authd service
4. Causing memory corruption that results in service crash or instability

The vulnerability does not require authentication to exploit, though successful exploitation depends on the attacker being able to reach the authd service endpoint. The attack results in denial of service through daemon crash, affecting the availability of agent authentication capabilities.

For detailed technical information about the vulnerability mechanism, refer to the GitHub Security Advisory and VulnCheck Advisory.

Detection Methods for CVE-2023-7340

Indicators of Compromise

• Unexpected crashes or restarts of the wazuh-authd daemon process
• Abnormal memory consumption patterns in the authd service prior to crash
• Malformed or unusually long authentication requests in network traffic to port 1515
• Core dumps or segmentation fault logs related to wazuh-authd

Detection Strategies

• Monitor wazuh-authd process stability and log any unexpected terminations
• Implement network intrusion detection rules to identify malformed authentication requests
• Deploy application-level monitoring to track heap memory allocation patterns in the authd daemon
• Analyze incoming traffic to the Wazuh manager for requests with unusual payload sizes or structures

Monitoring Recommendations

• Configure alerts for wazuh-authd service failures or repeated restarts
• Enable core dump collection for the authd process to aid in post-incident analysis
• Monitor network traffic to Wazuh manager authentication ports (typically 1515) for anomalies
• Review system logs for memory-related errors associated with the authentication daemon

How to Mitigate CVE-2023-7340

Immediate Actions Required

• Check your current Wazuh installation version and compare against affected releases
• Review network exposure of the wazuh-authd service and restrict access where possible
• Apply vendor-provided security patches as soon as they are available
• Consider temporarily disabling automatic agent registration if not operationally required

Patch Information

Wazuh has published a security advisory addressing this vulnerability. Organizations should consult the GitHub Security Advisory GHSA-grjq-p5fg-m24r for specific patch information and updated version details. Apply the recommended security updates according to your organization's change management procedures.

Workarounds

• Restrict network access to the authd service using firewall rules to limit exposure to trusted networks only
• Implement rate limiting on incoming connections to the authentication daemon
• Deploy network segmentation to isolate the Wazuh manager from untrusted network segments
• Monitor for and respond quickly to any detected service disruptions

# Configuration example - Restrict authd access via iptables
# Allow authd connections only from trusted agent subnets
iptables -A INPUT -p tcp --dport 1515 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 1515 -j DROP