What it is
RAR is a proprietary archive format that compresses one or more files into a single container with the .rar extension. It supports strong compression, error-recovery records, multi-part volumes, and self-extracting archives. Newer RAR versions add AES-256 encryption with password protection, so contents can be both smaller and locked.
Why it matters
RARs make large transfers faster and tidier, but they are also a common vehicle for malware. Encrypted archives can hide malicious payloads from casual inspection until a user extracts them.
How it works - quick tour
-
Compression: packs files with algorithms tuned for size.
-
Packaging: stores paths, timestamps, and optional recovery data.
-
Splitting: creates .part1.rar, .part2.rar for easier sharing.
-
Protection: optional password and AES encryption for contents and names.
Red flags
-
Unexpected RAR attachments from unknown senders.
-
Double extensions inside the archive like invoice.pdf.exe.
-
Archives that demand a password from the email body or a shady site.
-
Self-extracting RARs (.exe) that request admin rights.
Prevent it
-
Scan archives before opening and prefer extracting to a temporary folder.
-
Do not run executables directly from inside a RAR.
-
Be wary of password-protected archives you did not request.
-
Keep your archiver updated and block SFX extracts on locked-down systems.