Kingsoft WPS Office: file access flaw under attack

What is affected

Kingsoft WPS Office is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Kingsoft WPS Office contains a path traversal vulnerability in promecefpluginhost.exe on Windows that allows an attacker to load an arbitrary Windows library.

What an attacker can do

This is a file access flaw. It lets an attacker read or write files they should never reach, such as configuration files that hold passwords, or upload a malicious file that the system then runs.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

No account needed

Does the victim have to do something?

Yes, ordinary use is enough

What to do

1. Update Kingsoft WPS Office now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on September 3, 2024, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by September 24, 2024, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 2.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 87% of all scored vulnerabilities.

Its CVSS severity score is 9.3 out of 10 (critical), as recorded in the US National Vulnerability Database.

Technical description

Improper path validation in promecefpluginhost.exe in Kingsoft WPS Office version ranging from 12.2.0.13110 to 12.2.0.16412 (exclusive) on Windows allows an attacker to load an arbitrary Windows library. The vulnerability was found weaponized as a single-click exploit in the form of a deceptive spreadsheet document