Chinese Threat Actors Exploit ToolShell SharePoint Flaw Weeks After Microsoft's July Patch

Chinese Threat Actors Exploit ToolShell SharePoint Flaw Weeks After Microsoft’s July Patch

Oct 22, 2025Ravie LakshmananCyber Espionage / Vulnerability

Menace actors with ties to China exploited the ToolShell safety vulnerability in Microsoft SharePoint to breach a telecommunications firm within the Center East after it was publicly disclosed and patched in July 2025.

Additionally focused have been authorities departments in an African nation, in addition to authorities businesses in South America, a college within the U.S., in addition to doubtless a state expertise company in an African nation, a authorities division within the Center East, and a finance firm in a European nation.

In keeping with Broadcom’s Symantec Menace Hunter Staff, the assaults involved the exploitation of CVE-2025-53770, a now-patched safety flaw in on-premise SharePoint servers that might be used to bypass authentication and obtain distant code execution.

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CVE-2025-53770, assessed to be a patch bypass for CVE-2025-49704 and CVE-2025-49706, has been weaponized as a zero-day by three Chinese language menace teams, together with Linen Hurricane (aka Budworm), Violet Hurricane (aka Sheathminer), and Storm-2603, the latter of which is linked to the deployment of Warlock, LockBit, and Babuk ransomware households in current months.

Nevertheless, the newest findings from Symantec point out {that a} a lot wider vary of Chinese language menace actors have abused the vulnerability. This consists of the Salt Hurricane (aka Glowworm) hacking group, which is claimed to have leveraged the ToolShell flaw to deploy instruments like Zingdoor, ShadowPad, and KrustyLoader in opposition to the telecom entity and the 2 authorities our bodies in Africa.

KrustyLoader, first detailed by Synacktiv in January 2024, is a Rust-based loader beforehand put to make use of by a China-nexus espionage group dubbed UNC5221 in assaults exploiting flaws in Ivanti Endpoint Supervisor Cellular (EPMM) and SAP NetWeaver.

The assaults geared toward authorities businesses in South America and a college within the U.S., then again, concerned the usage of unspecified vulnerabilities to acquire preliminary entry, adopted by the exploitation of SQL servers and Apache HTTP servers operating the Adobe ColdFusion software program to ship the malicious payloads utilizing DLL side-loading methods.

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In among the incidents, the attackers have been noticed executing an exploit for CVE-2021-36942 (aka PetitPotam) for privilege escalation and area compromise, together with quite a lot of available and living-off-the-land (LotL) instruments to facilitate scanning, file obtain, and credential theft on the contaminated methods.

“There may be some overlap within the varieties of victims and among the instruments used between this exercise and exercise beforehand attributed to Glowworm,” Symantec mentioned. “Nevertheless, we wouldn’t have adequate proof to conclusively attribute this exercise to 1 particular group, although we will say that every one proof factors to these behind it being China-based menace actors.”

“The exercise carried out on focused networks signifies that the attackers have been taken with stealing credentials and in establishing persistent and stealthy entry to sufferer networks, doubtless for the aim of espionage.”

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