They may contain executables ( .exe ), scripts ( .js , .vbs ), or documents with malicious macros designed to infect your system.

Use a modern extraction tool like 7-Zip or WinRAR to "Open Archive" rather than "Extract Here" to see the file list without running them.

Check the ; extremely small files are often just "droppers" for viruses, while large files (hundreds of MBs) are more likely to be legitimate data or media.