Windows 11 Now Natively Supports Popular Archive Formats Including 7-Zip and RAR

Microsoft has rolled out an update¹ to its Windows 11 operating system, incorporating native support for a range of well-known archive formats, such as RAR and 7-Zip. The update leverages the libarchive open-source project, expanding the OS’s capabilities to handle eleven additional file formats: .tar, .tar.gz, .tar.bz2, .tar.zst, .tar.xz, .tgz, .tbz2, .tzst, .txz, .rar, and .7z. However, the tech giant specifies that password-encrypted files will not be supported.

Extended File Support: A Step Forward or a Security Concern?

For years, Windows has supported .zip files natively, but users had to rely on third-party software for other archive formats. This update, identified as KB5031455, is currently optional but will become mandatory for all Windows 11 users in the upcoming November Patch Tuesday.

Last year, cybersecurity firms pointed out an increasing trend among attackers using archive file types like RAR and ISO to disseminate malware². This was especially prevalent after Microsoft decided to block macros in Office 365 by default.

The inclusion of native support for these archive formats in Windows 11 raises questions about potential new avenues for cyberattacks.

1. https://support.microsoft.com/en-us/topic/october-26-2023-kb5031455-os-build-22621-2506-preview-6513c5ec-c5a2-4aaf-97f5-44c13d29e0d4 ↩︎
2. https://www.proofpoint.com/us/blog/threat-insight/how-threat-actors-are-adapting-post-macro-world ↩︎