CVE-2024-23577: HCL Aftermarket EPC Host Header Vulnerability

CVE-2024-23577 Overview

CVE-2024-23577 affects HCL Aftermarket EPC, a web application that fails to validate the HTTP Host header. The application accepts arbitrary values in the Host header when requests use the HTTP protocol. This weakness enables Host header poisoning and can lead to server misconfigurations, cache poisoning, and password reset link manipulation. The issue is tracked under CWE-20: Improper Input Validation. Exploitation requires user interaction, and attackers operate over the network without authentication. The flaw does not directly enable code execution but expands the attack surface for phishing and account takeover chains.

Critical Impact
Attackers can inject arbitrary Host header values, enabling web cache poisoning, password reset poisoning, and redirection to attacker-controlled infrastructure.

Affected Products

HCL Aftermarket EPC (Electronic Parts Catalog)
Deployments accepting HTTP protocol requests without header validation
Web-facing instances reachable over the network

Discovery Timeline

2026-07-17 - CVE-2024-23577 published to NVD
2026-07-17 - Last updated in NVD database

Technical Details for CVE-2024-23577

Vulnerability Analysis

The vulnerability stems from missing validation of the HTTP Host header on the Aftermarket EPC web tier. When a client sends an HTTP request, the application trusts the value supplied in the Host header without checking it against an allowlist of expected hostnames. An attacker can substitute an arbitrary domain and the application processes the request normally. Downstream components then use this attacker-controlled hostname when generating absolute URLs, cache keys, or password reset links. This behavior maps to CWE-20: Improper Input Validation. The EPSS score is 0.175% with a percentile of 7.173, indicating low near-term exploitation probability, though the weakness remains useful in targeted phishing chains.

Root Cause

The application does not compare the incoming Host header against a configured list of trusted hostnames. It also does not enforce HTTPS or reject requests that carry unexpected Host values. Server-side URL generation reuses the untrusted header value, propagating the poisoned input into responses, logs, and outbound emails.

Attack Vector

An attacker crafts an HTTP request to a legitimate Aftermarket EPC server with a malicious Host header pointing to an attacker-controlled domain. When the application generates a password reset email or absolute link, it embeds the attacker's hostname. A victim clicking the link is directed to the attacker's server, which harvests the reset token. The attack requires user interaction, typically via a phishing lure or a poisoned shared cache entry.

No verified public proof-of-concept code is available. Refer to the HCL Software Knowledge Base Article for vendor technical details.

Detection Methods for CVE-2024-23577

Indicators of Compromise

HTTP requests to Aftermarket EPC endpoints where the Host header value does not match the deployed server hostname or its documented aliases
Outbound password reset or notification emails containing links pointing to unexpected domains
Web server access logs showing repeated requests with rotating or suspicious Host header values from the same source IP

Detection Strategies

Compare the Host header in every request against a maintained allowlist of legitimate hostnames and alert on mismatches
Inspect application-generated URLs in outbound email traffic and flag hostnames that differ from the canonical application domain
Correlate anomalous Host header values with subsequent authentication or password reset activity to identify chained attacks

Monitoring Recommendations

Enable verbose HTTP request logging on reverse proxies and web application firewalls in front of Aftermarket EPC
Forward web tier logs to a centralized analytics platform to baseline expected Host header values and detect drift
Monitor DNS resolution logs for lookups from application servers to domains outside the approved allowlist

How to Mitigate CVE-2024-23577

Immediate Actions Required

Apply the vendor guidance published in the HCL Software Knowledge Base Article as soon as it is available for your deployment
Configure the fronting web server or load balancer to reject requests whose Host header does not match an explicit allowlist
Disable plain HTTP and enforce HTTPS with HTTP Strict Transport Security (HSTS) across all Aftermarket EPC endpoints

Patch Information

HCL Software has published remediation guidance for CVE-2024-23577 in knowledge base article KB0132294. Administrators should review the HCL Software Knowledge Base Article and apply the recommended configuration or product update to their Aftermarket EPC deployment.

Workarounds

Restrict the Aftermarket EPC application to a defined ServerName and reject requests with non-matching Host headers at the web server layer
Configure absolute URL generation in the application to use a static, server-side configured hostname rather than the incoming Host header
Place a web application firewall in front of Aftermarket EPC with a rule that validates the Host header against the approved domain list

bash

# Configuration example - Apache virtual host with strict Host header validation
<VirtualHost *:443>
    ServerName epc.example.com
    ServerAlias epc-internal.example.com

    # Reject requests whose Host header is not in the allowlist
    RewriteEngine On
    RewriteCond %{HTTP_HOST} !^(epc\.example\.com|epc-internal\.example\.com)$ [NC]
    RewriteRule ^ - [F]

    # Enforce HTTPS and HSTS
    Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains"
</VirtualHost>