Warlock Exploits SharePoint Flaws to Disable Security Tools and Deploy Ransomware
Warlock is exploiting SharePoint flaws to disable defenses and deploy ransomware against critical infrastructure and government targets.
Symantec and Carbon Black report that the suspected China-linked actor Warlock, also tracked as Storm-2603, Longlegs, and Gold Salem, continues to exploit on-premises Microsoft SharePoint flaws, including ToolShell, against Portuguese- and Spanish-speaking targets. In two months the group hit at least four organizations: a water utility, a telecommunications provider, a regional government body, and a university, across Europe, Africa, and Latin America. Intruders dropped web shells, collected ASP.NET machine keys to forge signed payloads, sideloaded DLLs, abused cloud storage, and used vulnerable driver K7RKScan.sys (CVE-2025-1055) to disable security tools. In one case they pushed a security-disabling tool to about 40 hosts and staged Warlock ransomware in SYSVOL so domain replication delivered it to at least 33 machines.
- Warlock hit a water utility, a telecom provider, a regional government, and a university.
- Attackers exploited on-premises SharePoint, planted web shells, and stole ASP.NET machine keys.
- They used BYOVD with K7RKScan.sys (CVE-2025-1055) to disable security tools.
- Ransomware was staged in SYSVOL and replicated to at least 33 hosts in one intrusion.
- ToolShell-related SharePoint flaws remain viable initial access on unpatched servers.
Vulnerabilities mentionedAll →
- CVE-2025-10555.6<1%A vulnerability in the K7RKScan.sys driver, part of the K7 Security Anti-Malware suite, allows a local low-privilege user to send crafted IOCTL requests to…published
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2025-1055 | A vulnerability in the K7RKScan.sys driver, part of the K7 Security Anti-Malware suite, allows a local low-privilege user to send crafted IOCTL requests to… A vulnerability in the K7RKScan.sys driver, part of the K7 Security Anti-Malware suite, allows a local low-privilege user to send crafted IOCTL requests to terminate a wide range of processes running with administrative or system-level privileges, with the exception of those inherently protected by the operating system. This flaw stems from missing access control in the driver's IOCTL handler, enabling unprivileged users to perform privileged actions in kernel space. Successful exploitation can lead to denial of service by disrupting critical services or privileged applications. |
Indicators of compromiseauto-extracted · verify before use · export allAll →
| Type | Indicator | Context |
|---|---|---|
| domain | catbox.moe | legitimate cloud file-sharing and storage services such as catbox[.]moe and wasabisys[.]com to fly under the radar. Abusing a leg |
| domain | wasabisys.com | file-sharing and storage services such as catbox[.]moe and wasabisys[.]com to fly under the radar. Abusing a legitimate-but-vulnerab |
Full article592 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananOct 03, 2026Vulnerability / Critical Infrastructure
The suspected China-linked threat actor known as Warlock is still continuing to weaponize Microsoft SharePoint vulnerabilities, likely both old and new, in attacks targeting organizations in Portuguese- and Spanish-speaking countries.
The activity, observed by the Symantec and Carbon Black Threat Hunter Team, has hit critical infrastructure, government, and education organizations.
"In the past two months, Longlegs has attacked at least four organizations, including two critical infrastructure operators (a water utility and a telecommunications provider), a regional government body, and a university," the Broadcom-owned cybersecurity unit said. "Victims were in Portuguese- and Spanish-speaking countries, spanning Europe, Africa, and Latin America."
Warlock, also tracked as Gold Salem, Longlegs, and Storm-2603, gained prominence in mid-2025 in connection with the zero-day exploitation of the "ToolShell" SharePoint flaws to deploy ransomware on targeted systems.
Earlier this year, the group was linked to the compromise of SmarterTools by exploiting an unpatched SmarterMail instance. It has also relied on legitimate tools like Velociraptor for command-and-control (C2) and the bring your own vulnerable driver (BYOVD) technique to disarm security software running on a compromised host.
According to Symantec, Warlock shares overlaps with older activity clusters known as CL-CRI-1040, CamoFei, and ChamelGang.
"In one intrusion against a critical infrastructure operator, the attackers pushed a tool designed to disable security software to at least 40 hosts within about two hours, then deployed Warlock on at least 33 hosts by staging it in the domain's SYSVOL share, where ordinary domain replication delivered it to machines," the researchers said.
Attacks mounted by Warlock have leveraged multiple vulnerabilities in on-premises Microsoft SharePoint Server deployments. Upon successfully finding a way in, the threat actors have been found to drop web shells that can target multiple versions of SharePoint.
The end goal of the web shell is to collect the SharePoint farm's ASP.NET machine keys, which are then abused to forge a validly signed payload and achieve remote code execution inside the SharePoint application pool.
Some of the other observed tactics are listed below -
- Using DLL sideloading to load malicious code into memory.
- Downloading follow-on payloads from legitimate cloud file-sharing and storage services such as catbox[.]moe and wasabisys[.]com to fly under the radar.
- Abusing a legitimate-but-vulnerable driver K7RKScan.sys (CVE-2025-1055) as part of a BYOVD attack to disable security software. The same driver was previously exploited by DragonForce ransomware actors.
- Using living-off-the-land (LotL) tooling to perform reconnaissance and run commands on the compromised hosts. This includes the abuse of Microsoft Visual Studio Code's built-in tunnel feature to facilitate remote connections to infected systems.
- Staging payloads inside the compromised domain's SYSVOL share to deploy ransomware at scale.
As recently as July 22, 2026, the threat actors are said to have exploited SharePoint Server flaws to drop a web shell, conduct discovery, obtain arbitrary code execution inside the SharePoint application pool, deploy additional payloads, burrow deeper into the network, establish VS Code tunnels, terminate security software, and ultimately deploy the ransomware binary.
"Longlegs' continued activity, more than a year after Warlock ransomware first came to prominence, shows that exploitation of ToolShell and other related-SharePoint vulnerabilities remains a viable initial access route for attackers SharePoint deployments that have not been patched or otherwise mitigated," Symantec and Carbon Black said.
"The apparent recent focus on Portuguese- and Spanish-speaking countries suggests either an opportunistic targeting pattern driven by exposed, vulnerable SharePoint servers, or a more deliberate tasking."
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