In May 2026, three malicious versions of Microsoft’s Azure Durable Task SDK were deployed to developers via GitHub, the developer repository owned and operated by Microsoft. The SDK is downloaded more than 400,000 times per month.
On June 5th, it happened again: this time, 73 Durable Task-related repositories, across four GitHub organizations – Azure, Azure-Samples, Microsoft, and MicrosoftDocs – were taken down in a matter of minutes by GitHub’s automated abuse monitor.
An analysis of the situation pointed to a malicious self-replicating worm called Misama, which was designed to collect login credentials such as passwords, API keys and authentication tokens stored on a developer’s computer. These credentials could be used to compromise applications running in generative AI environments operating in cloud infrastructures.
According to reporting by ArsTechnica, the compromise executed a 28 KB payload that steals credentials from AWS, Azure, GCP, Kubernetes, password managers, and over 90 developer tool configurations. The function would run as soon as a developer opened it in Claude Code, Gemini CLI, Cursor, VS Code and Github/setup.
The GitHub account used for this attack was the same one that was compromised to commit the attack in May.
Why it matters
These incidents illustrate that attacks by hackers operating against platforms that reside upstream from individual end users can have a much more widespread impact.
The worm steals cloud environment credentials (AWS, GCP, Azure), SSH keys, browser and wallet data, and pipeline secrets from system memory, which are often exposed publicly; attracting other hackers to commit further damage.
Further reading
Miasma worm hits Microsoft again: Azure functions action and 72 other repositories disabled after supply chain attack targeting AI coding agents. Article. June 5, 2026. by Ashish Kurmi. Step Security
For the 2nd time in weeks, Microsoft packages laced with credential stealer. Article. June 8, 2026. by Dan Goodin. Ars Technica
Hackers hijack Microsoft packages to steal developer logins. Article. June 9, 2026. by Anton Mous. Cybernews
The blight reaches Microsoft: 73 repos disabled in 105 seconds. Article. June 5, 2026. Opensource Malware blog
