"Wanna" ransomware outbreak. Please see this Sophos article sophos.com/kb/126733 for advice on how to protect your organization. Immediate action recommended.
This article describes how files are cached as Sophos Anti-Virus scans them, and provides instructions on how to clear the cache.
The following sections are covered:
Applies to the following Sophos products and versions Sophos Anti-Virus for Windows 2000+ 10.2.2 VDL4.84G
An updated file caching system was implemented in Sophos Anti-Virus 10.2, where the USN journal system is regularly queried to check for file changes.
Under certain conditions, if a file has not changed since the last time it was scanned, it need not be scanned again. This improves the system performance as files are not needlessly re-scanned.
The journal is ignored under the following conditions:
Clear the cache manually to ensure that all files are scanned once again.
NOTE: You cannot clear the on-demand scanner cache manually without clearing the on-access cache.
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