7-Zip 25.00 fixes vulnerabilities and speeds up compression

Version 25.00 of the widely used compression tool 7-Zip was released at the weekend. It speeds up some compression algorithms – and also closes security gaps.

In the development history on the 7-Zip homepage, developer Igor Pavlov briefly summarizes the new features. 7-Zip can now use more than 64 CPU threads for zip, 7z and xz compression under Windows. The built-in benchmark now also supports more threads. If several processor groups are available in Windows on systems with more than 64 processor cores, 7-Zip distributes the running CPU threads to the different CPU groups.

Pavlov was able to speed up bzip2 compression by 15 to 40 percent. The "deflate" compression for zip or gz is still 1 to 3 percent faster. However, the programmer does not explain how he was able to achieve speed gains. Support for zip, cpio and fat archives has also been improved in an unnamed way. In addition, the new version corrects "some errors and vulnerabilities", although he does not specifically name any of the latter. Nevertheless, 7-Zip users should update to the latest version as soon as possible.

7-Zip: Manual update necessary

As 7-Zip does not have an integrated update mechanism, users must download and install the update manually. The files for this can be downloaded directly from the 7-Zip website.

Recently, vulnerabilities in 7-Zip affecting the so-called "Mark of the Web" (MotW) have become known – Attackers have also successfully attacked such MotW vulnerabilities in 7-Zip. The mechanism means that Windows does not simply execute programs downloaded from the Internet, but at least displays a warning and requests confirmation from the user.

Microsoft Defender SmartScreen currently even blocks the freshly downloaded 7-Zip installer and does not start it. This will only work if the affected user activates the Mark-of-the-Web in the file properties by ticking the "Allow" option next to "Security: The file originates from another computer. Access may have been blocked for security reasons.".

The 7-Zip update can then be carried out.

(dmk)