CVE-2024-0695: Easy Chat Server 3.1 DOS Vulnerability

CVE-2024-0695 is a denial of service vulnerability in Easy Chat Server 3.1 affecting the HTTP GET Request Handler. Attackers can remotely exploit the USERNAME parameter to cause system unavailability. This article covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2024-0695 Overview

CVE-2024-0695 affects EFS Easy Chat Server 3.1, a Windows-based web chat application. The vulnerability resides in the HTTP GET request handler and is triggered by manipulating the USERNAME argument. A remote, unauthenticated attacker can send a crafted request to cause the server process to terminate, resulting in denial of service. The flaw is classified under CWE-404: Improper Resource Shutdown or Release. The exploit has been publicly disclosed through Packet Storm and referenced under VulDB entry VDB-251480. The vendor was contacted but did not respond to the disclosure.

Critical Impact
Remote, unauthenticated attackers can crash the Easy Chat Server 3.1 service by sending a malformed HTTP GET request, disrupting chat availability for all connected users.

Affected Products

EFS Easy Chat Server 3.1
CPE: cpe:2.3:a:easy_chat_server_project:easy_chat_server:3.1:*:*:*:*:*:*:*
HTTP GET Request Handler component

Discovery Timeline

2024-01-18 - CVE-2024-0695 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-0695

Vulnerability Analysis

Easy Chat Server 3.1 exposes an HTTP interface that processes user-supplied parameters in GET requests. The USERNAME parameter is not properly validated before being consumed by the server's request handling logic. Sending a specially crafted value causes the server process to terminate, matching the CWE-404 pattern of improper resource shutdown. The vulnerability requires no authentication and no user interaction. Confidentiality and integrity are not affected; only service availability is impacted. Public technical write-ups are available on Packet Storm and Exploit Alert.

Root Cause

The server fails to handle malformed or oversized values in the USERNAME HTTP GET parameter. Instead of rejecting the input, the handler enters an unrecoverable state and releases resources incorrectly, causing the process to exit. The vendor has not published source-level analysis, and no patch has been released.

Attack Vector

An attacker sends a single HTTP GET request to the vulnerable endpoint with a crafted USERNAME value. The request can originate from any host that reaches the listening TCP port over the network. Because the service runs without authentication for the affected endpoint, no credentials are required. Repeated requests can be used to keep the service offline whenever operators restart it. See the referenced VulDB entry for additional technical context.

Detection Methods for CVE-2024-0695

Indicators of Compromise

Unexpected termination of the Easy Chat Server process on Windows hosts running version 3.1.
HTTP GET requests targeting chat endpoints with unusually long or malformed USERNAME query parameters.
Repeated service restart events in Windows Event Log correlated with inbound HTTP traffic.

Detection Strategies

Inspect web proxy and IDS logs for GET requests containing anomalous USERNAME values directed at the Easy Chat Server listening port.
Correlate process-exit telemetry for the chat server binary with inbound network flows from external sources.
Deploy signature-based network detections that flag oversized query string parameters directed at legacy Easy File Sharing components.

Monitoring Recommendations

Alert on Easy Chat Server process crashes and automatic restarts within short time windows.
Track HTTP 4xx/5xx error rate spikes and connection resets on the chat service port.
Monitor for repeated source IP addresses issuing requests immediately preceding service termination.

How to Mitigate CVE-2024-0695

Immediate Actions Required

Restrict network access to Easy Chat Server 3.1 to trusted internal segments using host or perimeter firewalls.
Take the service offline if it is exposed to untrusted networks, given no vendor patch is available.
Inventory endpoints running EFS Easy Chat Server 3.1 and prioritize decommissioning or replacement.

Patch Information

No vendor patch is available. Per the NVD entry, the vendor was contacted early about this disclosure but did not respond. Organizations should treat Easy Chat Server 3.1 as unsupported and plan migration to an actively maintained chat platform.

Workarounds

Place the server behind a reverse proxy or web application firewall that enforces strict length and character validation on the USERNAME parameter.
Bind the service to loopback or an internal interface and require VPN access for legitimate users.
Disable the service until it can be replaced with a supported alternative.

bash

# Example Windows firewall rule to block external access to Easy Chat Server port (default 80)
netsh advfirewall firewall add rule name="Block-EasyChatServer-External" ^
  dir=in action=block protocol=TCP localport=80 ^
  remoteip=any profile=public,private