: Before opening, upload the file to VirusTotal to check it against dozens of antivirus engines.
: If the contents look like gibberice, you can use a hex editor to check the "Magic Bytes" at the start of the file to confirm it is actually a ZIP archive. pack 1373.zip
: Occasionally used by hardware manufacturers for specific internal build versions of firmware. : Before opening, upload the file to VirusTotal
: Use a tool like 7-Zip or WinRAR . Right-click the file and select "Open Archive" (instead of "Extract") to view the file tree and file extensions without executing anything. : Before opening