What is a Web Shell?

web shell attacks

A web shell is a term used to describe a malicious script written in any popular programming language. During a web shell attack, hackers inject a malicious file into the victim’s web server’s directory and then execute that file remotely. As a result, cybercriminals could gain access to sensitive information, create pathways for ransomware, modify files, and even reach the root directory of targeted servers – both internet-facing and non-internet-facing servers. Web shell attacks are easy to launch since they don’t require any additional programs. Web browsers may easily establish a communication connection using the HTTP protocol, that is why HTTPS protocols are so crucial.  

How Do Web Shell Attacks Work? 

Cyber attackers detect vulnerable servers with special scanning software that surfaces all internet-connected devices, including web servers and endpoints. After a vulnerability is discovered, hackers launch an attack immediately, before a security gap is patched. There are various web shell injection tactics, for instance the detection and compromise of Exposed Admin Interfaces, Cross-Site Scripting (XSS), and SQL injections. Ransomware attacks and data breaches usually don’t follow a web shell attack straight away. Cybercriminals use web shell attacks to create a channel for future malicious actions.

Detecting Web Shells. 

Web shells are not easy to detect since they can be hidden inside files that appear to be innocuous. A web shell script, for example, may be embedded in a photo and submitted to the target site. When this upload is analysed, nothing strange is found – after all, it is just a “photo”. Web servers refer to media files for server-side execution meaning a web browser can request the photo, which then activates malicious code. Security controls must be built in at the interface of internet-facing servers and the internet to check that every script file writes and process executions to overcome this. This layer of protection can be achieved through Defender for Endpoints by Microsoft or Shell Detector. 

How to Protect yourself from Web Shell Injections. 

Preventive measures are at the core of any reliable defence strategy. Discover five do’s to stay protected from Web shell injections. 

1. Install all the Latest Security Patches and Stay Updated 

The most typical vectors for web shell attacks are security gaps. Keep all web applications, Content Management Systems, web server software, and third-party software up to date with the latest security patches to block these entry points. 

2. Disable Unneeded Web Server Functions  

Web shell execution could be blocked if the functions that communicate with web server scripts are disabled in php.ini.  

3. Rename Sensitive Directories 

The default names of sensitive directories should be modified to make them more difficult to discover. Only users with privileged access should have permission to complete such actions to eliminate possibility of insider threat attacks. 

4. Disable unnecessary WordPress Plugins 

WordPress plugins are popular attack vectors because anyone can create them, including cybercriminals. To keep these vectors safe, only install plugins from reputable developers and delete any that aren’t needed. 

5. Monitor Your Attack Surface 

An attack surface monitoring solution analyses the full attack surface for vulnerabilities, both inside and over the vendor network. This enables security teams to address vulnerabilities before they are identified and exploited by cybercriminals. 

Always remember that delegating your cybersecurity to professionals is a great idea that optimizes resources and time. It can also potentially save your business from devastating cyber-attacks. Klik is here to help with reliable protection. Contact us and secure your business today. 

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