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Threat Hunter Team
Symantec and Carbon Black
China-based threat actors also compromised networks of government agencies in countries in Africa and South America.
China-based threat actors also compromised networks of government agencies in countries in Africa and South America.
Threat Intelligence
22 Oct 2025
7 Min Read
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China-based attackers used the ToolShell vulnerability (CVE-2025-53770) to compromise a telecoms company in the Middle East shortly after the vulnerability was publicly revealed and patched in July 2025.
The same threat actors also compromised two government departments in the same African country during the same time period. Zingdoor, which was deployed on the networks of all three organizations, has in the past been associated with the Chinese group Glowworm (aka Earth Estries, FamousSparrow).
Another tool used in this campaign, KrustyLoader, has also previously been linked to activity by a group called UNC5221, which has been described as a China-nexus group.
The attackers also gained access to the networks of two government agencies in South America and a university in the U.S. recently. In these attacks, the attackers used other vulnerabilities for initial access and exploited SQL servers and Apache HTTP servers running the Adobe ColdFusion software to deliver their malware. Notably, in the South American victims, the attackers used the filename “mantec.exe”, possibly to mimic a Symantec filename (“symantec.exe”) in an attempt to hide their malicious activity. This binary (mantec.exe), which is a legitimate copy of a BugSplat executable, a tool used for bug tracking, was used to sideload a malicious DLL.
Evidence suggests that a state technology agency in an African country, a government department in the Middle East and a finance company in a European country were also compromised by the same attackers.
What is ToolShell?
ToolShell was patched by Microsoft in July 2025, but by the time it was patched it had already been exploited in the wild as a zero-day vulnerability. ToolShell affects on-premise SharePoint servers and gives an attacker unauthenticated access to vulnerable servers, allowing them to remotely execute code and access all content and file systems. ToolShell was a variant of another vulnerability (CVE-2025-49704) that had been patched in July 2025. Another related vulnerability (CVE-2025-53771) was also patched at the same time as ToolShell. This is a path traversal bug that allows an authorized attacker to perform spoofing over a network. It too was a variant of an older patched vulnerability (CVE-2025-49706).
Shortly after patching the vulnerabilities, Microsoft said that at least three Chinese groups had been exploiting ToolShell. Microsoft said at the time that two Chinese espionage groups had been exploiting the vulnerability - Budworm (aka Linen Typhoon) and Sheathminer (aka Violet Typhoon). In addition to this, a third China-based actor, known as Storm-2603, was also exploiting the vulnerabilities to carry out attacks in which it was distributing the Warlock ransomware.
Toolset
Malicious activity in the telecoms company in the Middle East began on July 21, 2025, just two days after patches were published for ToolShell, with the deployment of a likely webshell by the attackers.
The attackers loaded the Zingdoor backdoor onto the network by sideloading it using a legitimate Trend Micro binary. Zingdoor is a HTTP backdoor written in Go, which was first seen in April 2023, and first documented by Trend Micro in August that year being used in a campaign that they attributed to Glowworm. Zingdoor can collect system information, upload and download files, and run arbitrary commands on compromised networks. As well as Zingdoor, the attackers also deployed what appears to be the ShadowPad Trojan. The loader for the Trojan was sideloaded using a legitimate BitDefender binary (SHA256: 3fc4f3ffce6188d3ef676f9825cdfa297903f6ca7f76603f12179b2e4be90134).
ShadowPad is a modular remote access Trojan (RAT) that is closely associated with China-based APT groups. Because of its modular nature, ShadowPad can be continuously updated with new functionalities. This capability makes it a powerful tool. It is associated with various threat groups, particularly the APT41-nexus groups such as Blackfly, Grayfly and Redfly. It was documented being used by Glowworm in 2024, which was the first time that particular group had been observed using the malware. It has more recently been used in attacks where ransomware has been deployed. Typically, ShadowPad is loaded onto victim networks via DLL sideloading. DLL sideloading is a technique where the attackers use the DLL search order mechanism in Windows to plant and then invoke a legitimate application that executes a malicious DLL payload.
On July 25, KrustyLoader was dropped by the attackers. KrustyLoader was first documented in January 2024. It is an initial-stage malware, written in Rust, which has the primary purpose of delivering a second-stage payload. KrustyLoader can carry out various anti-sandbox and anti-analysis checks, can make a copy of itself and set itself up to self-delete when its activity is finished, and can decrypt and download additional malware. Its previous activity has been linked to China-based threat actors, and in earlier campaigns it was also used to download the Sliver post-exploitation framework, which is also seen deployed against this target.
Sliver is an open-source cross-platform adversary emulation/red team framework that can legitimately be used for security testing. However, it is often abused by threat actors who use it as a command-and-control framework.
A variety of publicly available and living-off-the-land tools are also used by the attackers in this activity, including:
Certutil: Microsoft Windows utility that can be used for various malicious purposes, such as to decode information, to download files, and to install browser root certificates.
GoGo Scanner: A publicly available automated scanning engine aimed at Chinese speaking users, for use by red teams. It is available on GitHub.
Revsocks: A publicly available cross-platform SOCKS5 proxy server program/library written in C that can also reverse itself over a firewall.
Procdump: Microsoft Sysinternals tool for monitoring an application for CPU spikes and generating crash dumps, but can also be used as a general process dump utility.
Minidump: A script from the post-exploitation framework PowerSploit used for dumping processes. Attackers usually dump lsass.exe to find credentials.
LsassDumper: A utility designed to dump the Local Security Authority Subsystem Service (LSASS) process memory to a file.
An exploit for the Windows LSA Spoofing Vulnerability, CVE-2021-36942 (aka PetitPotam), was also executed. PetitPotam is an exploitation technique that allows for a threat actor within a compromised network to steal credentials and authentication information from Windows Servers such as a Domain Controller to gain full control of the domain. This is likely used for lateral movement or privilege escalation.
ToolShell impact further revealed
These attacks demonstrate that the ToolShell vulnerability was being exploited by an even wider range of Chinese threat actors than was originally thought.
There is some overlap in the types of victims and some of the tools used between this activity and activity previously attributed to Glowworm. However, we do not have sufficient evidence to conclusively attribute this activity to one specific group, though we can say that all evidence points to those behind it being China-based threat actors.
The large number of apparent victims of this activity is also notable. This may indicate that the attackers were carrying out an element of mass scanning for the ToolShell vulnerability, before then carrying out further activity only on networks of interest. The activity carried out on targeted networks indicates that the attackers were interested in stealing credentials and in establishing persistent and stealthy access to victim networks, likely for the purpose of espionage.
Indicators of Compromise (IOCs)
File indicators
6240e39475f04bfe55ab7cba8746bd08901d7678b1c7742334d56f2bc8620a35 - LsassDumper
929e3fdd3068057632b52ecdfd575ab389390c852b2f4e65dc32f20c87521600 - KrustyLoader
db15923c814a4b00ddb79f9c72f8546a44302ac2c66c7cc89a144cb2c2bb40fa - Likely ShadowPad
e6c216cec379f418179a3f6a79df54dcf6e6e269a3ce3479fd7e6d4a15ac066e – ShadowPad Loader
071e662fc5bc0e54bcfd49493467062570d0307dc46f0fb51a68239d281427c6 - Zingdoor
1f94ea00be79b1e4e8e0b7bbf2212f2373da1e13f92b4ca2e9e0ffc5f93e452b - PetitPotam/CVE-2021-36942 exploit
dbdc1beeb5c72d7b505a9a6c31263fc900ea3330a59f08e574fd172f3596c1b8 - RevSocks
6aecf805f72c9f35dadda98177f11ca6a36e8e7e4348d72eaf1a80a899aa6566 - LsassDumper
568561d224ef29e5051233ab12d568242e95d911b08ce7f2c9bf2604255611a9 - Socks Proxy
28a859046a43fc8a7a7453075130dd649eb2d1dd0ebf0abae5d575438a25ece9 - GoGo Scanner
7be8e37bc61005599e4e6817eb2a3a4a5519fded76cb8bf11d7296787c754d40 - Sliver
5b165b01f9a1395cae79e0f85b7a1c10dc089340cf4e7be48813ac2f8686ed61 - ProcDump
e4ea34a7c2b51982a6c42c6367119f34bec9aeb9a60937836540035583a5b3bc - ProcDump
7803ae7ba5d4e7d38e73745b3f321c2ca714f3141699d984322fa92e0ff037a1 – Minidump
7acf21677322ef2aa835b5836d3e4b8a6b78ae10aa29d6640885e933f83a4b01 - mantec.exe – Benign executable
6c48a510642a1ba516dbc5effe3671524566b146e04d99ab7f4832f66b3f95aa - bugsplatrc.dll
Network indicators
http://kia-almotores.s3.amazonaws[.]com/sy1cyjt - KrustyLoader C&C server
http://omnileadzdev.s3.amazonaws[.]com/PBfbN58lX - KrustyLoader C&C server
Unknown threat actors have breached the National Nuclear Security Administration's network in attacks exploiting a recently patched Microsoft SharePoint zero-day vulnerability chain.
NNSA is a semi-autonomous U.S. government agency part of the Energy Department that maintains the country's nuclear weapons stockpile and is also tasked with responding to nuclear and radiological emergencies within the United States and abroad.
A Department of Energy spokesperson confirmed in a statement that hackers gained access to NNSA networks last week.
"On Friday, July 18th, the exploitation of a Microsoft SharePoint zero-day vulnerability began affecting the Department of Energy, including the NNSA," Department of Energy Press Secretary Ben Dietderich told BleepingComputer. "The Department was minimally impacted due to its widespread use of the Microsoft M365 cloud and very capable cybersecurity systems."
Dietderich added that only "a very small number of systems were impacted" and that "all impacted systems are being restored."
As first reported by Bloomberg, sources within the agency also noted that there's no evidence of sensitive or classified information compromised in the breach.
The APT29 Russian state-sponsored threat group, the hacking division of the Russian Foreign Intelligence Service (SVR), also breached the U.S. nuclear weapons agency in 2019 using a trojanized SolarWinds Orion update.
Attacks linked to Chinese state hackers, over 400 servers breached
On Tuesday, Microsoft and Google linked the widespread attacks targeting a Microsoft SharePoint zero-day vulnerability chain (known as ToolShell) to Chinese state-sponsored hacking groups.
"Microsoft has observed two named Chinese nation-state actors, Linen Typhoon and Violet Typhoon exploiting these vulnerabilities targeting internet-facing SharePoint servers," Microsoft said.
"In addition, we have observed another China-based threat actor, tracked as Storm-2603, exploiting these vulnerabilities. Investigations into other actors also using these exploits are still ongoing."
Dutch cybersecurity firm Eye Security first detected the zero-day attacks on Friday, stating that at least 54 organizations had already been compromised, including national government entities and multinational companies.
Cybersecurity firm Check Point later revealed that it had spotted signs of exploitation going back to July 7th targeting dozens of government, telecommunications, and technology organizations in North America and Western Europe.
krebsonsecurity.com - On Sunday, July 20, Microsoft Corp. issued an emergency security update for a vulnerability in SharePoint Server that is actively being exploited to compromise vulnerable organizations. The patch comes amid reports that malicious hackers have used the SharePoint flaw to breach U.S. federal and state agencies, universities, and energy companies.
In an advisory about the SharePoint security hole, a.k.a. CVE-2025-53770, Microsoft said it is aware of active attacks targeting on-premises SharePoint Server customers and exploiting vulnerabilities that were only partially addressed by the July 8, 2025 security update.
The Cybersecurity & Infrastructure Security Agency (CISA) concurred, saying CVE-2025-53770 is a variant on a flaw Microsoft patched earlier this month (CVE-2025-49706). Microsoft notes the weakness applies only to SharePoint Servers that organizations use in-house, and that SharePoint Online and Microsoft 365 are not affected.
The Washington Post reported on Sunday that the U.S. government and partners in Canada and Australia are investigating the hack of SharePoint servers, which provide a platform for sharing and managing documents. The Post reports at least two U.S. federal agencies have seen their servers breached via the SharePoint vulnerability.
According to CISA, attackers exploiting the newly-discovered flaw are retrofitting compromised servers with a backdoor dubbed “ToolShell” that provides unauthenticated, remote access to systems. CISA said ToolShell enables attackers to fully access SharePoint content — including file systems and internal configurations — and execute code over the network.
Researchers at Eye Security said they first spotted large-scale exploitation of the SharePoint flaw on July 18, 2025, and soon found dozens of separate servers compromised by the bug and infected with ToolShell. In a blog post, the researchers said the attacks sought to steal SharePoint server ASP.NET machine keys.
“These keys can be used to facilitate further attacks, even at a later date,” Eye Security warned. “It is critical that affected servers rotate SharePoint server ASP.NET machine keys and restart IIS on all SharePoint servers. Patching alone is not enough. We strongly advise defenders not to wait for a vendor fix before taking action. This threat is already operational and spreading rapidly.”
Microsoft’s advisory says the company has issued updates for SharePoint Server Subscription Edition and SharePoint Server 2019, but that it is still working on updates for supported versions of SharePoint 2019 and SharePoint 2016.
CISA advises vulnerable organizations to enable the anti-malware scan interface (AMSI) in SharePoint, to deploy Microsoft Defender AV on all SharePoint servers, and to disconnect affected products from the public-facing Internet until an official patch is available.
The security firm Rapid7 notes that Microsoft has described CVE-2025-53770 as related to a previous vulnerability — CVE-2025-49704, patched earlier this month — and that CVE-2025-49704 was part of an exploit chain demonstrated at the Pwn2Own hacking competition in May 2025. That exploit chain invoked a second SharePoint weakness — CVE-2025-49706 — which Microsoft unsuccessfully tried to fix in this month’s Patch Tuesday.
Microsoft also has issued a patch for a related SharePoint vulnerability — CVE-2025-53771; Microsoft says there are no signs of active attacks on CVE-2025-53771, and that the patch is to provide more robust protections than the update for CVE-2025-49706.
This is a rapidly developing story. Any updates will be noted with timestamps.
forbes.com - Microsoft has confirmed that SharePoint Server is under mass attack and no patch is yet available — here’s what you need to know and how to mitigate the threat.
Microsoft Confirms CVE-2025-53770 SharePoint Server Attacks
It’s been quite the few weeks for security warnings, what with Amazon informing 220 million customers of Prime account attacks, and claims of a mass hack of Ring doorbells going viral. The first of those can be mitigated by basic security hygiene, and the latter appears to be a false alarm. The same cannot be said for CVE-2025-53770, a newly uncovered and confirmed attack against users of SharePoint Server which is currently undergoing mass exploitation on a global level, according to the Eye Research experts who discovered it. Microsoft, meanwhile, has admitted that not only is it “aware of active attacks” but, worryingly, “a patch is currently not available for this vulnerability.”
CVE-2025-53770, which is also being called ToolShell, is a critical vulnerability in on-premises SharePoint. The end result of which is the ability for attackers to gain access and control of said servers without authentication. If that sounds bad, it’s because it is. Very bad indeed.
“The risk is not theoretical,” the researchers warned, “attackers can execute code remotely, bypassing identity protections such as MFA or SSO.” Once they have, they can then “access all SharePoint content, system files, and configurations and move laterally across the Windows Domain.”
And then there’s the theft of cryptographic keys. That can enable an attacker to “impersonate users or services,” according to the report, “even after the server is patched.” So, even when a patch is eventually released, and I would expect an emergency update to arrive fairly quickly for this one, the problem isn’t solved. You will, it was explained, “need to rotate the secrets allowing all future tokens that can be created by the malicious actor to become invalid.”
And, of course, as SharePoint will often connect to other core services, including the likes of Outlook and Teams, oh and not forgetting OneDrive, the threat, if exploited, can and will lead to “data theft, password harvesting, and lateral movement across the network,” the researchers warned.
