CVE-2022-28331: Apache Portable Runtime Buffer Overflow

CVE-2022-28331 Overview

CVE-2022-28331 is an Integer Overflow vulnerability affecting Apache Portable Runtime (APR) on Windows systems. On Windows, Apache Portable Runtime 1.7.0 and earlier may write beyond the end of a stack based buffer in apr_socket_sendv(). This is a result of integer overflow, which can lead to memory corruption and potentially allow attackers to execute arbitrary code or cause denial of service conditions.

Critical Impact

This vulnerability enables remote attackers to exploit the integer overflow condition in apr_socket_sendv() to write beyond stack buffer boundaries, potentially achieving remote code execution or causing system crashes on Windows systems running vulnerable APR versions.

Affected Products

• Apache Portable Runtime versions 1.7.0 and earlier
• Microsoft Windows (all versions when running vulnerable APR)
• Applications utilizing Apache Portable Runtime on Windows platforms

Discovery Timeline

• 2023-01-31 - CVE CVE-2022-28331 published to NVD
• 2025-03-27 - Last updated in NVD database

Technical Details for CVE-2022-28331

Vulnerability Analysis

This vulnerability is classified as CWE-190 (Integer Overflow or Wraparound). The flaw exists within the apr_socket_sendv() function, which is used for scatter/gather I/O operations on network sockets. When processing vector I/O buffers on Windows platforms, the function performs arithmetic operations on buffer sizes that can result in integer overflow conditions.

The integer overflow occurs during the calculation of buffer lengths before memory operations. When an attacker supplies specially crafted input values, the arithmetic overflow causes the calculated buffer size to wrap around to a smaller value than intended. Subsequently, the function writes data beyond the allocated stack buffer boundaries, creating a stack-based buffer overflow condition.

This type of vulnerability is particularly dangerous because stack-based buffer overflows can potentially overwrite return addresses or other critical stack data, enabling attackers to hijack program execution flow.

Root Cause

The root cause is improper handling of integer arithmetic in the apr_socket_sendv() function on Windows. The function fails to validate that the sum of buffer lengths does not exceed the maximum representable integer value before allocating and writing to stack buffers. When the sum overflows, a smaller-than-expected buffer size is used, but the original larger amount of data is written, causing the overflow.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can exploit this vulnerability by sending maliciously crafted network requests to an application using the vulnerable apr_socket_sendv() function. The attack involves:

1. Identifying an application utilizing Apache Portable Runtime on Windows
2. Crafting network requests with buffer parameters designed to trigger the integer overflow
3. Sending the malicious payload to cause the stack buffer overflow
4. Potentially achieving code execution by overwriting stack return addresses

The vulnerability mechanism involves integer overflow during buffer size calculations in the scatter/gather I/O operations. When multiple buffer lengths are summed for the sendv() operation, the result can wrap around to a small positive value if the combined size exceeds the maximum integer value. The function then allocates an undersized stack buffer while attempting to copy the full amount of data, resulting in a stack buffer overflow. For detailed technical analysis, refer to the Apache Security Advisory.

Detection Methods for CVE-2022-28331

Indicators of Compromise

• Unexpected application crashes or segmentation faults in applications using Apache Portable Runtime
• Abnormal network traffic patterns with unusually large or malformed buffer parameters
• Stack corruption or memory access violations in APR-dependent processes
• Unusual process behavior or unexpected child process spawning from APR-based applications

Detection Strategies

• Deploy network intrusion detection rules to identify anomalous scatter/gather I/O patterns targeting APR-based applications
• Monitor for crash dumps and exceptions indicating stack buffer overflows in APR libraries
• Implement application-level logging to detect unusual buffer size parameters in network operations
• Use memory protection technologies to detect stack smashing attempts

Monitoring Recommendations

• Enable Windows Event Log monitoring for application crashes related to APR-dependent services
• Configure endpoint detection and response (EDR) solutions to alert on stack-based buffer overflow exploitation attempts
• Monitor system calls and API usage patterns for apr_socket_sendv() with anomalous parameters
• Implement network flow analysis to detect potential exploitation traffic targeting vulnerable services

How to Mitigate CVE-2022-28331

Immediate Actions Required

• Inventory all systems running Apache Portable Runtime on Windows platforms
• Upgrade Apache Portable Runtime to versions later than 1.7.0 that contain the fix
• Apply network segmentation to limit exposure of vulnerable systems
• Enable stack protection mechanisms such as ASLR and stack canaries on affected systems

Patch Information

Apache has released a security update to address this vulnerability. Organizations should upgrade to Apache Portable Runtime versions beyond 1.7.0 that contain the fix for this integer overflow vulnerability. Consult the Apache Security Advisory for specific patch details and updated version information.

Workarounds

• Restrict network access to affected services using firewalls or access control lists
• Implement Web Application Firewalls (WAF) with rules to filter potentially malicious requests
• Consider disabling or limiting the use of vector I/O operations where feasible
• Deploy runtime application self-protection (RASP) solutions to detect and block exploitation attempts

# Configuration example - Restrict network access to APR-based services
# Windows Firewall rule to limit inbound connections
netsh advfirewall firewall add rule name="Restrict APR Service" dir=in action=block protocol=tcp localport=<service_port> remoteip=any
# Allow only trusted networks
netsh advfirewall firewall add rule name="Allow Trusted APR Access" dir=in action=allow protocol=tcp localport=<service_port> remoteip=<trusted_network_cidr>