A reported Free Download Manager supply chain attack redirected Linux users to a malicious Debian package repository that installed information-stealing malware.
The malware used in this campaign establishes a reverse shell to a C2 server and installs a Bash stealer that collects user data and account credentials.
Kaspersky discovered the potential supply chain compromise case while investigating suspicious domains, finding that the campaign has been underway for over three years.
The key thing to know is that a client can do an HTTP HEAD
request to get just the Content-Length
of the file, and then perform GET
requests with the Range
request header to fetch a specific chunk of a file.
This mechanism was introduced in HTTP 1.1 (byte-serving).