Executive Summary

This vulnerability is a denial of service (DoS) issue in Mocha Telnet Lite for iOS version 4.2. It occurs because the application improperly handles the 'User' configuration input field. An attacker can input 350 bytes of repeated characters into this field, causing the application to crash and preventing it from functioning normally. This crash is triggered by a buffer overflow when the 'User' field is overwritten with the specially crafted input. [1, 2]

Useful 0 Not Useful 0

Impact Analysis

The impact of this vulnerability is a denial of service condition where the Mocha Telnet Lite app crashes and becomes unusable when the 'User' field is manipulated with a crafted input. This disrupts normal functionality of the app, preventing users from establishing Telnet connections until the app is restarted or reconfigured. It does not affect confidentiality or integrity, but availability is impacted locally. [1, 2]

Useful 0 Not Useful 0

Detection Guidance

This vulnerability can be detected by attempting to reproduce the denial of service condition locally on the iOS device running Mocha Telnet Lite 4.2. A known method is to input a specially crafted string of 350 repeated characters into the 'User' field during configuration, which causes the app to crash. A proof-of-concept Python script is available to generate this buffer. The detection steps include: 1) Run the Python script to generate 350 'A' characters. 2) Copy the output to the clipboard. 3) Open Mocha Telnet Lite on the iOS device. 4) Navigate to 'Configure' and add a new configuration. 5) Set the IP address to '192.168.1.1'. 6) Paste the buffer into the 'User' field. 7) Set the password to 'l4m5'. 8) Navigate back twice and attempt to connect. If the app crashes, the vulnerability is present. [1]

Useful 0 Not Useful 0

Mitigation Strategies

Immediate mitigation steps include avoiding inputting excessively long or malformed strings into the 'User' field of the Mocha Telnet Lite app configuration. Users should refrain from using untrusted or automated inputs that could trigger the buffer overflow. Additionally, monitoring for app crashes during configuration changes can help identify exploitation attempts. Since the vulnerability requires local user interaction, restricting access to the device and ensuring only trusted users configure the app can reduce risk. Applying any available updates or patches from the vendor when released is also recommended. [1, 2]

Useful 0 Not Useful 0

Compliance Impact

The provided information does not specify any impact of this vulnerability on compliance with common standards and regulations such as GDPR or HIPAA.

Useful 0 Not Useful 0