LibSSH Flaw Allows Hackers to Take Over Servers Without Password

October 19, 2018 Published in: News Author: Vedran Bozicevic

A four-year-old severe vulnerability has been discovered in the Secure Shell (SSH) implementation library known as Libssh that could allow anyone to completely bypass authentication and gain unfettered administrative control over a vulnerable server without requiring a password.

The security vulnerability, tracked as CVE-2018-10933, is an authentication-bypass issue that was introduced in Libssh version 0.6 released earlier 2014, leaving thousands of enterprise servers open to hackers for the last four years

According to a security advisory published Tuesday, all an attacker needs to do is sending an “SSH2_MSG_USERAUTH_SUCCESS” message to a server with an SSH connection enabled when it expects an “SSH2_MSG_USERAUTH_REQUEST” message.

Due to a logical flaw in libssh, the library fails to validate if the incoming “successful login” packet was sent by the server or the client, and also fails to check if the authentication process has been completed or not.

Therefore, if a remote attacker (client) sends this “SSH2_MSG_USERAUTH_SUCCESS” response to libssh, it considers that the authentication has been successful and will grant the attacker access to the server, without needing to enter a password.

Read more: The Hacker News

Vedran Bozicevic

I am a digital marketer with several years of experience with various types of online marketing technologies and channels. Before joining GlobalDots, my experience included working as a content marketing manager for a software development company, and several others marketing positions where I worked on digital marketing strategies and channels.

Our Story

 

GlobalDots helps companies to evaluate, purchase, and integrate cloud services by acting as a neutral consultancy layer between vendors and customers with a keen focus on optimizing performance, workflows, and costs.

We're in the unique position to orchestrate full-stack, multi-vendor architectures such as multi-CDN, CDN+WAF+AWS, CDN+Mobile App optimization, dual-DNS, and other interesting setups.

Increase speed, availability and reliability of your website by learning from the experts in our FREE email course.

Learn everything you need to know about Bad Bot threats by downloading your FREE copy of Bad Bot Report 2018.

Find out the most important tips&tricks before selecting your next CDN provider in this FREE guide.

Find out all the specifics about web threats by downloading our FREE Field Guide to Modern Web Security.