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Grief Ransomware Gang Claims 41 New Victims, Targeting Manufacturers; Municipalities; & Service Companies in U.K. & Europe
Grief Operators Earned an Estimated 8.5 Million British Pounds in Four Months Key Findings: The Grief Ransomware Gang (a rebrand of the DoppelPaymer Ransomware Group) claims to have infected 41 new victims between May 27, 2021—Oct. 1, 2021 with their ransomware.Over half the companies listed on Grief’s underground leak site are based in the U.K. and Europe. The Grief Ransomware Gang appears to…
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Security advisories — Feb 26, 2019

Malicious .SLK Files

External sources have identified the limited use of maliciously crafted Symbolic Link files (.SLK) in phishing campaigns. Spreadsheet applications are used to launch and execute the malicious PowerShell command contained inside. This infection vector does not require the use of macros, making standard detection less likely.

At this time, .SLK files do not appear to be commonly incorporated into phishing campaigns. There is a Medium confidence rating that this delivery method will be widely adopted by threat actors in the near future.

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Additional information

Symbolic Link files using the “.SLK” file extension are used to transfer data between spreadsheets and other databases. These files are primarily used by Microsoft Office but are also recognized by other products in Windows, Mac, Linux, iOS and Android [1].

Protected view does not appear to be an option when opening .SLK files directly. Fortunately, there are multiple security notifications before a malicious .SLK file can be executed; the end user must agree to at least three separate prompts. These prompts limit the likelihood of success but do not eliminate the chance that a user may unwittingly permit the malicious activity.

[1] https://fileinfo.com/extension/slk