KINWILDER

Fox Tempest

No sourced public emblem in this profile.

reference profile · reported nexus: Unknown (not nationality)

Fox Tempest is a financially motivated threat actor that operated a malware-signing-as-a-service (MSaaS) sold to other cybercriminals to sign malware, including ransomware, as trusted software and evade detection. The service, marketed through the domain signspace[.]cloud and a Telegram channel, abused Microsoft Artifact Signing to issue short-lived fraudulent code-signing certificates and offered signing plans priced between 5,000 and 9,000 USD, with higher tiers providing pre-configured virtual machines for signing malicious code. Microsoft tracked the operation from September 2025 and observed its certificates used to distribute malware families such as Oyster, Lumma Stealer, and Vidar and to support ransomware activity linked to Vanilla Tempest, Storm-0501, Storm-2561, and Storm-0249. In May 2026, Microsoft's Digital Crimes Unit disrupted the operation, seizing signspace[.]cloud, taking hundreds of signing virtual machines offline, and revoking more than 1,000 fraudulent certificates, and named Vanilla Tempest as a co-defendant in a case filed in the U.S. District Court for the Southern District of New York.

Source-reported aliases: . Associations do not prove equivalence.

Target geography

Catalog-listed countries (associations, not attack counts): No country-level metadata

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Historical casebook

No dated record curated yet; absence does not establish inactivity.

Planned Kinwilder coverage

Tentative editorial review windows, contingent on evidence and review; not promised publication dates or predictions of attacks.

No assigned review window.

References

Pinned source catalog

https://www.microsoft.com/en-us/security/blog/2026/05/19/exposing-fox-tempest-a-malware-signing-service-operation/

https://blogs.microsoft.com/on-the-issues/2026/05/19/disrupting-fox-tempest-a-cybercrime-service/

https://therecord.media/microsoft-disrupts-fox-tempest-malware-signing-service

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