HttpClient is a type of malware that exploits a vulnerability in the Apache HttpClient software. The malware takes advantage of insufficient validation of user-supplied input to send an HTTP GET request to a specified asset URL using the .NET framework's "HttpClient" class DLL file. Once the malware has infiltrated a system, it can cause damage to the computer or device, steal personal information, disrupt operations, or hold data hostage for ransom.
The vulnerability that HttpClient exploits exists because Apache Commons HttpClient does not properly verify that the server hostname matches a domain name in the X.509 certificate's subject's Common Name (CN) or subjectAltName field. This makes it possible for HttpClient to execute code on the system without proper authentication. While Apache issued patches to address this vulnerability, it remains a potential threat to systems that have not applied the necessary updates.
To prevent falling victim to the HttpClient malware, users should be cautious when downloading files, opening emails, or accessing suspicious websites. It is also important to keep systems up to date with the latest security patches. By doing so, users can help mitigate the risk of infection and protect their personal information from being compromised.