CVE-2024-28038: Web Interface Buffer Overflow Vulnerability

CVE-2024-28038 Overview

CVE-2024-28038 is a critical stack buffer overflow vulnerability affecting the web interface of Sharp and Toshiba Tec multifunction printer (MFP) devices. The vulnerability occurs when the web interface improperly processes the MFPSESSIONID cookie parameter, allowing an attacker to trigger a stack buffer overflow by supplying an excessively long character string. This memory corruption vulnerability can potentially lead to arbitrary code execution on affected devices.

Critical Impact

Remote attackers can exploit this stack buffer overflow vulnerability via the network without authentication, potentially gaining complete control over affected MFP devices and compromising confidentiality, integrity, and availability of the system.

Affected Products

• Sharp MFP devices (refer to Sharp security advisories for specific model numbers)
• Toshiba Tec MFP devices (refer to Toshiba Tec security notices for specific model numbers)
• Additional affected vendors listed in JVN vulnerability report JVNVU93051062

Discovery Timeline

• 2024-05-31 - Security advisories released by Sharp and Toshiba Tec
• 2024-11-26 - CVE-2024-28038 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2024-28038

Vulnerability Analysis

This vulnerability is classified as CWE-121 (Stack-based Buffer Overflow). The root cause lies in improper bounds checking when the web interface processes cookie values. Specifically, the MFPSESSIONID parameter handler fails to validate the length of input data before copying it to a fixed-size stack buffer. When an attacker supplies a cookie value that exceeds the buffer's allocated size, the overflow corrupts adjacent stack memory, potentially overwriting the return address and other critical control data.

The attack can be executed remotely over the network without requiring any privileges or user interaction. However, exploitation requires overcoming certain complexity factors, which may include address space layout randomization (ASLR) or other memory protection mechanisms present on the embedded system.

Root Cause

The vulnerability stems from insufficient input validation in the web server component of the affected MFP devices. The code responsible for parsing and storing the MFPSESSIONID cookie parameter uses an unsafe copy operation that does not properly verify that the input length fits within the destination buffer on the stack. This classic memory safety issue allows attackers to write beyond the buffer boundaries.

Attack Vector

The attack is conducted over the network by sending a specially crafted HTTP request to the web interface of the vulnerable MFP device. The attacker includes a malicious MFPSESSIONID cookie with an oversized value designed to overflow the stack buffer. A successful exploit could allow the attacker to:

1. Overwrite the saved return address on the stack
2. Redirect execution flow to attacker-controlled code or ROP gadgets
3. Achieve arbitrary code execution with the privileges of the web server process
4. Potentially gain full control of the MFP device

The vulnerability does not require authentication, making it accessible to any attacker with network access to the device's web interface. Technical details and proof-of-concept information have been documented in Pierre Kim's security research blog covering multiple Sharp MFP vulnerabilities.

Detection Methods for CVE-2024-28038

Indicators of Compromise

• Unusually large HTTP cookie values in web server logs, particularly targeting the MFPSESSIONID parameter
• Web server crashes or unexpected service restarts on MFP devices
• Anomalous network traffic patterns to MFP device web interfaces
• Signs of unauthorized access or configuration changes on MFP devices

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests containing abnormally long cookie values (exceeding typical session ID lengths)
• Monitor MFP device logs for web server errors, crashes, or segmentation faults
• Deploy web application firewalls (WAF) or reverse proxies with request size limits in front of MFP web interfaces
• Use SentinelOne Singularity to detect exploitation attempts and anomalous process behavior on network-connected devices

Monitoring Recommendations

• Enable comprehensive logging on MFP devices and forward logs to a centralized SIEM solution
• Establish baseline network behavior for MFP devices and alert on deviations
• Regularly audit MFP device configurations for unauthorized changes
• Monitor for reconnaissance activity targeting MFP device web interfaces

How to Mitigate CVE-2024-28038

Immediate Actions Required

• Apply vendor security patches from Sharp and Toshiba Tec immediately
• Restrict network access to MFP device web interfaces using firewall rules or network segmentation
• Disable web interface access from untrusted networks if not required for operations
• Place MFP devices on isolated network segments with limited access

Patch Information

Security updates addressing CVE-2024-28038 have been released by the affected vendors. Refer to the official security advisories for specific patch information:

• Sharp Global Security Update 2024
• Sharp Japan Print Security Info 2024
• Toshiba Tec Security Notice 2024
• Toshiba Tec Security Information 2024

Additional vulnerability details are available in the JVN Vulnerability Report JVNVU93051062.

Workarounds

• Implement strict network access controls to limit access to MFP web interfaces to authorized management systems only
• Deploy a web application firewall or reverse proxy to filter and validate incoming HTTP requests before they reach MFP devices
• If the web interface is not required for normal operations, disable it entirely until patches can be applied
• Consider implementing VPN-only access for remote administration of MFP devices

# Example: Restrict MFP web interface access using iptables
# Allow only management subnet to access MFP web interface
iptables -A INPUT -p tcp --dport 80 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP