Checking for preinstalled backdoor functionality

Details of BNVL-2018-0042

What does the BNVL label mean?

BitNinja Server Security’s BNVL identifiers are intended for use to identify publicly known information security vulnerabilities in publicly released software packages. This project was designed to collect and analyze attack information from the BitNinja network after cluster analysis by the AI-powered Attack Vector Miner. More than 100 vulnerability types have been discovered with this project so far, so we decided to publish this platform to help to keep Linux server owners up-to-date.

Important! All listed BNVL vulnerabilities are protected by BitNinja PRO, so please check your configurations if your infrastructure is affected by any of them.

Syntax for BNVL labels:

BNVL prefix + Year + Arbitrary Digits

Name :
Checking for preinstalled backdoor functionality
Related Links: Na



The request is a test for a previously installed PHP backdoor. The c&c server is sending a small string and then checks the result to test if the backdoor is still functional or not.

Pattern: dd