CVE-2018-25266: Angry IP Scanner Buffer Overflow Flaw

CVE-2018-25266 Overview

CVE-2018-25266 is a buffer overflow vulnerability affecting Angry IP Scanner version 3.5.3. The vulnerability exists in the preferences dialog component and allows local attackers to crash the application by supplying an excessively large string input. An attacker can generate a file containing a massive buffer of repeated characters and paste it into the unavailable value field in the display preferences to trigger a denial of service condition.

Critical Impact

Local attackers can cause application crashes and denial of service by exploiting improper input validation in the preferences dialog, potentially disrupting network scanning operations.

Affected Products

• Angry IP Scanner 3.5.3

Discovery Timeline

• 2026-04-22 - CVE CVE-2018-25266 published to NVD
• 2026-04-22 - Last updated in NVD database

Technical Details for CVE-2018-25266

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), which occurs when the application writes data past the end or before the beginning of an intended buffer. In the context of Angry IP Scanner 3.5.3, the preferences dialog fails to properly validate the length of user-supplied input before processing it, leading to a buffer overflow condition.

The attack requires local access to the system where Angry IP Scanner is installed. An attacker does not need special privileges or user interaction to exploit this vulnerability once they have local access. The vulnerability specifically targets the display preferences functionality, where the "unavailable value" field can be manipulated with oversized input strings.

While this vulnerability does not allow for code execution or data theft, it can effectively disable the network scanning application, causing availability impact to users relying on the tool for network reconnaissance and management tasks.

Root Cause

The root cause of this vulnerability lies in inadequate input validation and boundary checking within the preferences dialog code. When processing user input for the display preferences settings, specifically the unavailable value field, the application fails to enforce proper length restrictions on the input string. This allows an attacker to supply an excessively large buffer that overflows the allocated memory space, causing memory corruption and subsequent application crash.

Attack Vector

The attack vector is local, requiring the attacker to have access to the system where Angry IP Scanner is installed. The exploitation method involves preparing a malicious file containing an extremely large string of repeated characters (a massive buffer), then pasting this content into the unavailable value field within the display preferences dialog. When the application attempts to process this oversized input, it overflows the designated buffer space and causes the application to crash.

This attack is straightforward to execute and does not require sophisticated technical knowledge. The denial of service impact is limited to the Angry IP Scanner application itself and does not affect system stability beyond the application crash. Technical details and proof-of-concept information can be found in the Exploit-DB #45993 advisory.

Detection Methods for CVE-2018-25266

Indicators of Compromise

• Unexpected crashes or termination of the Angry IP Scanner application
• Presence of abnormally large text files or clipboard content on the system
• Error logs indicating memory access violations or buffer overflow exceptions in the application
• Repeated application restarts correlated with user activity in preferences dialogs

Detection Strategies

• Monitor for application crash events specifically related to the Angry IP Scanner process (ipscan.exe on Windows, ipscan on Linux/macOS)
• Implement endpoint detection rules to identify attempts to paste extremely large strings into application input fields
• Configure crash dump analysis to capture memory state during application failures for forensic review

Monitoring Recommendations

• Enable application-level logging in Angry IP Scanner to track configuration changes and preferences modifications
• Deploy endpoint protection solutions capable of detecting anomalous application behavior patterns
• Monitor system event logs for repeated application fault events associated with ipscan processes

How to Mitigate CVE-2018-25266

Immediate Actions Required

• Upgrade Angry IP Scanner to a version newer than 3.5.3 if available from the vendor
• Restrict local access to systems running Angry IP Scanner to trusted users only
• Consider alternative network scanning tools if an updated version is not available
• Implement application allowlisting to prevent unauthorized modifications to the Angry IP Scanner configuration

Patch Information

Users should check the Angry IP Scanner official website for the latest version releases and security updates. Review the VulnCheck Advisory for additional guidance on remediation steps.

Workarounds

• Limit local access to systems running Angry IP Scanner to only essential personnel
• Use read-only deployment configurations where preferences cannot be modified by end users
• Deploy the application in isolated environments where denial of service impact is minimized
• Consider running the application under a restricted user account with limited clipboard access

# Example: Restrict file permissions on Linux/macOS
chmod 755 /path/to/ipscan
chown root:users /path/to/ipscan
# Ensure only trusted users can execute the application