CVE-2022-28330: Apache HTTP Server Buffer Overflow Flaw

CVE-2022-28330 Overview

CVE-2022-28330 is an out-of-bounds read vulnerability affecting Apache HTTP Server 2.4.53 and earlier versions running on Microsoft Windows. The vulnerability occurs when the server is configured to process requests using the mod_isapi module, potentially allowing remote attackers to read memory beyond intended bounds and access sensitive information.

Critical Impact

Remote attackers can exploit this vulnerability to read sensitive data from server memory without authentication, potentially exposing confidential information processed by the Apache HTTP Server on Windows systems.

Affected Products

• Apache HTTP Server versions up to and including 2.4.53
• Microsoft Windows (all supported versions running affected Apache HTTP Server)
• Systems with mod_isapi module enabled and configured

Discovery Timeline

• 2022-06-09 - CVE-2022-28330 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-28330

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory corruption issue that occurs when the mod_isapi module processes certain requests. The flaw allows the server to read data from memory locations outside the intended buffer boundaries, which can result in information disclosure.

The mod_isapi module provides Internet Server Application Programming Interface (ISAPI) extension support for Apache HTTP Server on Windows platforms. When processing specially crafted requests, the module fails to properly validate buffer boundaries, allowing read operations to access adjacent memory regions.

This vulnerability is network-accessible and requires no privileges or user interaction to exploit, making it particularly concerning for internet-facing Apache installations on Windows with ISAPI extensions enabled.

Root Cause

The root cause of CVE-2022-28330 lies in improper bounds checking within the mod_isapi module when handling request data. The module does not adequately validate the length of input data against allocated buffer sizes before performing read operations. This allows an attacker to craft requests that trigger the server to read beyond the allocated memory buffer, potentially exposing sensitive data stored in adjacent memory regions.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Sending specially crafted HTTP requests to an Apache HTTP Server running on Windows with mod_isapi enabled
2. The malformed request triggers the out-of-bounds read condition in the ISAPI module
3. Memory contents beyond the intended buffer are read and potentially returned to the attacker
4. Repeated exploitation attempts may reveal progressively more sensitive information from server memory

The vulnerability can be exploited through the network attack vector, making any publicly accessible Apache HTTP Server on Windows with the vulnerable configuration a potential target. The exploit does not require sophisticated tooling, though no public proof-of-concept code has been published.

Detection Methods for CVE-2022-28330

Indicators of Compromise

• Unusual HTTP requests targeting ISAPI extensions with malformed or oversized parameters
• Server log entries showing abnormal request patterns to .dll extension handlers
• Memory access violations or unexpected server behavior logged in Windows Event Viewer
• Network traffic analysis showing repeated probing of ISAPI-configured endpoints

Detection Strategies

• Monitor Apache access logs for unusual request patterns targeting ISAPI extensions
• Implement network intrusion detection rules to identify malformed ISAPI requests
• Deploy web application firewalls (WAF) with rules to detect out-of-bounds read exploitation attempts
• Use SentinelOne's real-time endpoint detection to identify memory access anomalies

Monitoring Recommendations

• Enable verbose logging for the mod_isapi module to capture detailed request information
• Configure alerting for unusual memory consumption patterns on Apache processes
• Implement file integrity monitoring for Apache configuration files and ISAPI DLLs
• Monitor for unexpected information disclosure in HTTP responses

How to Mitigate CVE-2022-28330

Immediate Actions Required

• Upgrade Apache HTTP Server to version 2.4.54 or later immediately
• If upgrade is not immediately possible, disable the mod_isapi module
• Review and restrict network access to Apache servers running on Windows
• Implement network segmentation to limit exposure of vulnerable systems

Patch Information

Apache has addressed this vulnerability in Apache HTTP Server version 2.4.54 and later releases. Administrators should upgrade to the latest available version to remediate this vulnerability. Detailed patch information and release notes are available in the Apache HTTP Server Vulnerabilities advisory.

Additional vendor advisories include the NetApp Security Advisory NTAP-20220624-0005 for systems running Apache HTTP Server on NetApp products.

Workarounds

• Disable mod_isapi module if ISAPI functionality is not required for your deployment
• Implement strict input validation at the network perimeter using a WAF
• Configure access control lists to limit which clients can access ISAPI endpoints
• Consider migrating ISAPI extensions to alternative technologies not affected by this vulnerability

If disabling mod_isapi is not possible, the following configuration can restrict access to ISAPI handlers:

# Restrict access to ISAPI handlers
<IfModule mod_isapi.c>
    <LocationMatch "\.dll$">
        Require ip 10.0.0.0/8
        Require ip 192.168.0.0/16
        # Deny all other access
    </LocationMatch>
</IfModule>