--- title: "BlueHammer Microsoft Defender Flaw Exploited in Ransomware Attacks" url: https://daily.dev/posts/bluehammer-microsoft-defender-flaw-exploited-in-ransomware-attacks-epvsqsotd source_url: https://securityboulevard.com/2026/07/bluehammer-microsoft-defender-flaw-exploited-in-ransomware-attacks type: article source: "Security Boulevard" published: 2026-07-01T07:08:33.006Z updated: 2026-07-01T07:08:59.420Z tags: ["security", "ransomware"] reading_time: 3 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # BlueHammer Microsoft Defender Flaw Exploited in Ransomware Attacks **[Security Boulevard](https://daily.dev/sources/securityboulevard)** · 3 min read · 0 upvotes · 0 comments ## Summary CISA has updated its Known Exploited Vulnerabilities catalog to confirm that CVE-2026-33825, a Microsoft Defender privilege escalation flaw dubbed BlueHammer, has been actively exploited in ransomware attacks. The vulnerability was publicly disclosed on April 2 before Microsoft released patches on April 14, and security firm Huntress observed zero-day exploitation in the wild. CISOs are advised to verify patch deployment, monitor KEV catalog updates for ransomware-use designations (not just new entries), and hunt for post-compromise privilege escalation activity in endpoint telemetry. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [CISA: Windows BlueHammer flaw now exploited by ransomware gangs](https://daily.dev/posts/cisa-windows-bluehammer-flaw-now-exploited-by-ransomware-gangs-8msc5m9tl) · BleepingComputer · 1 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#ransomware](https://daily.dev/tags/ransomware) [View this post on daily.dev](https://daily.dev/posts/bluehammer-microsoft-defender-flaw-exploited-in-ransomware-attacks-epvsqsotd)