Extra data has emerged on the current ToolShell zero-day assaults focusing on Microsoft SharePoint Server cases, together with on impacted organizations, the variety of compromised servers, and the risk actors exploiting the vulnerabilities.
Information of the ToolShell assaults emerged over the weekend, when Microsoft and safety companies warned that SharePoint zero-day vulnerabilities had been exploited to hack servers. The tech big rushed to launch patches for impacted SharePoint variations which might be nonetheless supported, however initially solely mitigations have been accessible and people have since been bypassed.
The primary public stories of assaults have been triggered by exploitation makes an attempt seen on July 18, however Microsoft revealed on July 22 that it had discovered proof of ToolShell exploitation commencing on July 7, roughly one week earlier than researchers warned of the potential impression of the vulnerabilities.
Microsoft has seen assaults carried out by two Chinese language state-sponsored cyberespionage teams, named Linen Hurricane and Violet Hurricane.
The corporate has additionally seen assault makes an attempt by a risk actor it tracks as Storm-2603. This group, which Microsoft has linked to China with reasonable confidence, has been noticed deploying ransomware in ToolShell assaults carried out since July 18.
“Though Microsoft has noticed this risk actor deploying Warlock and Lockbit ransomware previously, Microsoft is at present unable to confidently assess the risk actor’s goals,” the corporate mentioned on Wednesday.
Over 400 SharePoint Server cases hacked; US authorities victims are named
Eye Safety, the primary cybersecurity agency to report seeing assaults, revealed on Wednesday that its researchers have scanned greater than 23,000 SharePoint servers and decided that not less than 400 of them have been compromised throughout 4 assault waves carried out on July 17, July 18, July 19 and July 21. Commercial. Scroll to proceed studying.
Cybersecurity firms reported inside days of the ToolShell assaults coming to gentle that US authorities businesses had been among the many victims.
A number of mainstream media publications have reported studying from sources that authorities organizations had been focused, however the numbers vary from 4 to over a dozen impacted businesses.
Some publications have named impacted businesses primarily based on data from their sources. Nextgov realized that the Division of Homeland Safety (DHS) was impacted, whereas Bloomberg realized that the Power Division’s Nationwide Nuclear Safety Administration was breached in a ToolShell assault, in addition to the Training Division and a few state authorities businesses.
The Washington Submit reported that the Division of Well being and Human Companies’ Nationwide Institutes of Well being (NIH) was additionally hit.
The scope of most of those breaches remains to be being assessed, the publications realized from sources, however the Nuclear Safety Administration mentioned it had discovered no proof of delicate or categorised data getting compromised.
Confusion stays over which SharePoint vulnerabilities have been exploited
When information of the SharePoint zero-day assaults broke, it was broadly reported {that a} distant code execution vulnerability tracked as CVE-2025-53770 has been exploited. It later got here to gentle that it might have been chained with a spoofing flaw, CVE-2025-53771.
CVE-2025-53770 and CVE-2025-53771 have been assigned by Microsoft on account of patches for CVE-2025-49706 and CVE-2025-49704 being bypassed. CVE-2025-49706 and CVE-2025-49704 have been disclosed in Might on the Pwn2Own hacking competitors they usually have been patched by Microsoft on July 8.
In its weblog publish, Microsoft says it has seen exploitation of CVE-2025-49706 and CVE-2025-49704. Nevertheless, the corporate’s advisories for these vulnerabilities, in addition to for CVE-2025-53771, don’t point out in-the-wild exploitation.
SecurityWeek has reached out to Microsoft and a number of other cybersecurity companies for clarifications and thus far solely WatchTowr has confirmed seeing exploitation of each CVE-2025-53770 and CVE-2025-53771.
A number of main firms, together with Palo Alto Networks, SentinelOne, Google, Development Micro, and CrowdStrike, couldn’t affirm exploitation of CVE-2025-53771, regardless of a few of their weblog posts suggesting it.
Microsoft has refused to share any clarifications, however its newest weblog publish signifies that CVE-2025-53770 permits each authentication bypass and distant code execution, which might clarify why CVE-2025-53771 might not be wanted in assaults.
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