H Microsoft said the team security of detects approximately 77.000 active web shells daily, scattered on 46.000 infected servers.
This number is much larger than all its previous reports company.
What are they? world wide web shells;
The huge number that Microsoft has pointed out highlights their preference hackers in particular tools. Web shells are a must-have tool for any attacker, from small hacktivist groups to state-based hacking teams specializing in espionage.
Web shells are essential malware or scripts installed in hacked servers.
They provide a visual interface, which hackers can use to interact with the hacked server and its file system. Most web shells allow you to rename, copy, move and even edit or upload files to the server. They still can steal data from the server.
Attackers usually install web shells, exploiting them vulnerabilities in servers and web applications (such as CMS, CMS plugins, CMS themes, CRMs, intranets, etc.).
Web shells can be written to any programming language. This allows hackers to hide them in the source code of any site. Therefore, it is difficult to detect them by an expert without the help of a web firewall or a web malware scanner.
There is usually one with the web shell backdoor script. Attackers attack a server, install the web shell to interact with the filesystem, and then install a backdoor, which allows hackers to re-infect the system if the webshell is detected and removed.
The most popular web shell nowadays is China Chopper. It was first observed in 2012 and was created by Chinese hackers. It was released in a Chinese hacking forum and adopted by cybercriminals around the world.
Microsoft warned system administrators not to ignore this threat. Hackers often use these malicious scripts to download others hacking tools in systems of the victims. These tools are, in turn, used to carry out attacks.