User enumeration in Universal Robots Control Box CB3.x

by vmayoral
macOS ◆ xterm-256color ◆ zsh 1348 views

We found that the Universal Robots Controllers’ file system based in Debian is subject to CVE-2016-6210 which allows attackers to perform unauthenticated user enumeration. The flaw affects OpenSSH which is exposed by default in port 22.

The reason why OpenSSH is vulnerable is because before version 7.3, when SHA256 or SHA512 are used for user password hashing, it uses BLOWFISH hashing on a static password when the username does not exist. This allows remote attackers to enumerate users by leveraging the timing difference between responses when a large password is provided figuring out which users are valid and which ones aren’t.