Microsoft GitHub Repositories Hit by Miasma Supply Chain Attack
Microsoft’s GitHub repositories have been targeted in the ongoing Miasma self-replicating supply chain attack, affecting 73 repositories across four organizations Azure, Azure-Samples, Microsoft, and MicrosoftDocs. GitHub has disabled access to the compromised repositories, displaying a terms-of-service violation notice for affected projects, including Azure/azure-functions-host.
Among the impacted repositories are key projects such as durabletask (and its related .NET, Go, JavaScript, and MSSQL implementations), azure-search-openai-demo-purviewdatasecurity, and windows-driver-docs. Notably, the durabletask PyPI package was previously compromised by TeamPCP in May to distribute an information stealer on Linux systems, suggesting the same threat actors may still retain access.
Miasma, a variant of the Mini Shai-Hulud worm released by TeamPCP in mid-2026, has evolved its tactics, infecting additional packages in recent days. Attackers have created new repositories with deceptive descriptions like "Miasma: The Spreading Blight" and "Hades - The End for the Damned", with 95 such repositories identified so far.
The campaign has also bypassed traditional registry-based attacks, directly injecting malicious code into repositories like icflorescu/mantine-datatable and related projects. The payload a 4.3 MB runner executes automatically when developers open affected repositories in AI coding tools such as Claude Code, Gemini CLI, Cursor, or VS Code, or via the npm test script.
Security researchers highlight that Miasma exploits the trust model underpinning open-source ecosystems, propagating through legitimate channels without relying on platform vulnerabilities. By compromising maintainer credentials and mimicking routine updates, the attack evades conventional defenses, making it one of the most persistent and far-reaching supply chain campaigns to date.
Source: https://thehackernews.com/2026/06/miasma-worm-hits-73-microsoft-github.html
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"id": "MICMICMICGIT1780813480",
"linkid": "microsoft, microsoft-security, microsoft-azure, github",
"type": "Cyber Attack",
"date": "5/2026",
"severity": "100",
"impact": "5",
"explanation": "Attack threatening the organization's existence"{'affected_entities': [{'customers_affected': 'Developers using affected '
'repositories',
'industry': 'Software, Cloud Computing',
'name': 'Microsoft (GitHub Repositories)',
'type': 'Technology Company'},
{'customers_affected': 'Developers using Azure-related '
'repositories',
'industry': 'Cloud Computing',
'name': 'Azure',
'type': 'Cloud Service Provider'},
{'customers_affected': 'Developers using Azure sample '
'repositories',
'industry': 'Software Development',
'name': 'Azure-Samples',
'type': 'Code Samples Repository'},
{'customers_affected': 'Developers using Microsoft '
'documentation repositories',
'industry': 'Software Development',
'name': 'MicrosoftDocs',
'type': 'Documentation Repository'}],
'attack_vector': 'Compromised maintainer credentials, malicious code '
'injection into repositories',
'description': 'Microsoft’s GitHub repositories have been targeted in the '
'ongoing *Miasma* self-replicating supply chain attack, '
'affecting 73 repositories across four organizations: Azure, '
'Azure-Samples, Microsoft, and MicrosoftDocs. The attack has '
'compromised key projects such as *durabletask*, '
'*azure-search-openai-demo-purviewdatasecurity*, and '
'*windows-driver-docs*. The *Miasma* worm, a variant of *Mini '
'Shai-Hulud* released by *TeamPCP*, has evolved its tactics, '
'infecting additional packages and bypassing traditional '
'registry-based attacks. The payload executes automatically '
'when developers open affected repositories in AI coding tools '
'or via the *npm test* script.',
'impact': {'brand_reputation_impact': 'Potential erosion of trust in '
"open-source ecosystems and Microsoft's "
'GitHub repositories',
'operational_impact': 'Disabled access to compromised '
'repositories, terms-of-service violation '
'notices',
'systems_affected': 'GitHub repositories, AI coding tools (Claude '
'Code, Gemini CLI, Cursor, VS Code)'},
'initial_access_broker': {'entry_point': 'Compromised maintainer credentials',
'high_value_targets': 'Key projects like '
'*durabletask*, '
'*azure-search-openai-demo-purviewdatasecurity*, '
'and *windows-driver-docs*'},
'lessons_learned': 'The attack exploits the trust model in open-source '
'ecosystems, highlighting the need for enhanced security '
'measures in maintainer credentials and repository '
'updates.',
'post_incident_analysis': {'root_causes': 'Exploitation of trust in '
'open-source ecosystems, '
'self-replicating worm propagation, '
'compromised maintainer '
'credentials'},
'recommendations': 'Implement stricter access controls for maintainer '
'credentials, enhance monitoring of repository updates, '
'and educate developers on supply chain attack risks.',
'response': {'containment_measures': 'Disabled access to compromised '
'repositories, terms-of-service '
'violation notices'},
'threat_actor': 'TeamPCP',
'title': 'Microsoft GitHub Repositories Hit by Miasma Supply Chain Attack',
'type': 'Supply Chain Attack',
'vulnerability_exploited': 'Trust model in open-source ecosystems, '
'self-replicating worm propagation'}