Clop
Cl0p is a ransomware family and associated extortion operation active since 2019, widely described as a successor to CryptoMix and also referred to as Clop/CLOP. It has targeted organizations across many industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications, healthcare, government, and critical infrastructure. Reporting in the provided content links Cl0p to TA505, FIN11, Lace Tempest, DEV-0950, and UNC2546.
The malware and operation are associated with both traditional ransomware and data-theft extortion. The content states that Cl0p has used double extortion and, in major campaigns such as GoAnywhere and MOVEit, shifted to pure extortion focused on exfiltrated data rather than encryption. It is specifically noted as one of the few ransomware actors to repeatedly exploit zero-day vulnerabilities, especially in managed file transfer products.
Observed capabilities and behaviors in the content include: checking keyboard language and character set via GetKeyboardLayout() and GetTextCharset to avoid installation on Russian-language or other CIS-language systems; uninstalling or disabling security products; using code signing to evade detection; deleting shadow copies with "vssadmin Delete Shadows /all /quiet"; and using bcdedit to disable recovery options. Additional reporting notes use of net.exe, taskkill.exe, and vssadmin.exe during encryption-related activity, and Mandiant analyzed a CLOP sample with a hardcoded process termination list that included OT-related strings.
Initial access and infection vectors described in the content include phishing campaigns historically associated with TA505/FIN11, as well as exploitation of public-facing file transfer software vulnerabilities. Specific exploitation campaigns mentioned include Accellion FTA in 2020; SolarWinds Serv-U CVE-2021-35211, where attackers used PowerShell to deploy Cobalt Strike and abused the RegIdleBackup scheduled task to load FlawedGrace RAT; GoAnywhere MFT CVE-2023-0669; MOVEit Transfer CVE-2023-34362 and related 2023 MOVEit flaws, where specially crafted webshells were used to enumerate and steal files and Azure Blob Storage credentials/secrets; and Cleo Harmony, VLTrader, and LexiCom via CVE-2024-50623 and CVE-2024-55956, where attackers deployed malicious Freemarker template backdoor code and the Java backdoor Malichus for command execution, data theft, and further access.
The content associates Cl0p with large-scale victimization and extortion campaigns, including the MOVEit mass exploitation campaign and attacks affecting organizations such as South Staffordshire Water. Reported victim sectors and impacts include broad enterprise compromise, downstream third-party exposure, and incidents involving sensitive personal data theft. High-confidence indicators and artifacts directly mentioned in the content include the command lines "vssadmin Delete Shadows /all /quiet" and bcdedit recovery-disabling activity; Serv-U log evidence containing "EXCEPTION: C0000005; CSUSSHSocket::ProcessReceive();"; abuse of the RegIdleBackup task and suspicious COM handler changes; and the Cleo-associated Malichus backdoor.
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Vulnerabilities exploited
23 CVEs Mallory has correlated with this family across public research and vendor advisories. Each row links to the full Mallory page for that vulnerability.
PaperCut servers have been previously breached by ransomware gangs in 2023 by exploiting a critical, unauthenticated remote code execution (RCE) vulnerability (CVE–2023–27350)... One month later, CISA and the FBI issued a joint advisory warning that the Bl00dy Ransomware gang had also begun exploiting the CVE-2023–27350 RCE vulnerability to gain initial access to the networks of educational organizations.
PaperCut servers have been previously breached by ransomware gangs in 2023 by exploiting a critical, unauthenticated remote code execution (RCE) vulnerability (CVE–2023–27350) and a high-severity information disclosure flaw (CVE–2023–27351).
On 11 October 2025, Oracle released an emergency fix for a high-severity information disclosure vulnerability in Oracle E-Business Suite (EBS), tracked as CVE-2025-61884. The flaw exists in the Runtime UI component of Oracle Configurator and allows remote unauthenticated threat actors to access sensitive resources.
On October 4, 2025, Oracle released a fix for a newly disclosed critical vulnerability, tracked as CVE-2025-61882, linked to recent extortion emails received by some Oracle E-Business Suite (EBS) customers. This vulnerability allows unauthenticated remote threat actors to achieve remote code execution and resides in the BI Publisher component of Oracle Concurrent Processing.
Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare. | Cl0p exploited a zero-day vulnerability in Cleo LexiCom, Cleo VLTrader, and Cleo Harmony products to steal data. The vulnerability, tracked as CVE-2024-50623, enables remote file uploads and downloads, leading to remote code execution. A fix has been released for affected Cleo products (version 5.8.0.21), but researchers have warned that the patch may be bypassed. Huntress disclosed the active exploitation of the vulnerability and provided a proof-of-concept to demonstrate its potential impact.
Cl0p is a type of ransomware that has been used in cyberattacks since 2019. | On May 31st, Progress Software issued an advisory and patch for a vulnerability subsequently identified as CVE-2023-34362 and assigned a severity rating of 9.8 out of 10. The company stated the vulnerability “could lead to escalated privileges and potential unauthorized access to the environment.” In other words, it was a vulnerability which could enable hackers to access MOVEit and steal data – something which it later emerged had been happening since at least May 27th.
CL0P have utilized this tactic in the targeting of organizations using a vulnerable version of ‘Accellion FTA’, a file transfer appliance. As such, following vulnerabilities have reportedly been exploited to gain access to victim data as well as potentially pivoting into victim networks: CVE-2021-27101 – Critical SQL Injection via a crafted Host header in versions ≤9_12_370. | Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
CL0P have utilized this tactic in the targeting of organizations using a vulnerable version of ‘Accellion FTA’, a file transfer appliance. As such, following vulnerabilities have reportedly been exploited to gain access to victim data as well as potentially pivoting into victim networks: CVE-2021-27104 – Critical command execution via a crafted POST in versions ≤9_12_370. | Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
CL0P have utilized this tactic in the targeting of organizations using a vulnerable version of ‘Accellion FTA’, a file transfer appliance. As such, following vulnerabilities have reportedly been exploited to gain access to victim data as well as potentially pivoting into victim networks: CVE-2021-27102 – Command execution via a local web service call in versions ≤9_12_411. | Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
CL0P have utilized this tactic in the targeting of organizations using a vulnerable version of ‘Accellion FTA’, a file transfer appliance. As such, following vulnerabilities have reportedly been exploited to gain access to victim data as well as potentially pivoting into victim networks: CVE-2021-27103 – Critical server-side request forgery (SSRF) in versions ≤9_12_411. | Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
The Clop ransomware gang, also tracked as TA505 and FIN11, is exploiting a SolarWinds Serv-U vulnerability to breach corporate networks and ultimately encrypt its devices. The Serv-U Managed File Transfer and Serv-U Secure FTP remote code execution vulnerability, tracked as CVE-2021-35211, allows a remote threat actor to execute commands on a vulnerable server with elevated privileges. | The Clop ransomware gang, also tracked as TA505 and FIN11, is exploiting a SolarWinds Serv-U vulnerability to breach corporate networks and ultimately encrypt its devices.
Cl0p is a type of ransomware that has been used in cyberattacks since 2019.
Cl0p is a type of ransomware that has been used in cyberattacks since 2019.
The Clop ransomware gang has confirmed to BleepingComputer that they are behind the recent Cleo data-theft attacks, utilizing zero-day exploits tracked as CVE-2024-50623 and CVE-2024-55956 to breach corporate networks and steal data.
Further, two of their domain controllers were left completely unpatched against ZeroLogon (CVE-2020-1472), a critical, easily exploitable vulnerability published years before the intrusion.
These threat actors have expanded their attacks by exploiting two additional vulnerabilities (CVE-2025-11371 and CVE-2025-30406) to bypass authentication controls, execute malicious code, and steal data on the target server. CVE-2025-30406 ... A vulnerability caused due to CentreStack portal’s hardcoded machinekey use. Enables threat actors to serialize a payload server-side deserialization to achieve RCE.
These threat actors have expanded their attacks by exploiting two additional vulnerabilities (CVE-2025-11371 and CVE-2025-30406) to bypass authentication controls, execute malicious code, and steal data on the target server. In the default installation and configuration of Gladinet CentreStack and TrioFox, there is an unauthenticated Local File Inclusion Flaw that allows unintended disclosure of system files. Exploitation of this vulnerability has been observed in the wild.
CISA added CVE-2025-14611 to its Known Exploited Vulnerabilities (KEV) Catalog on Dec. 15, 2025. This critical insecure cryptography vulnerability affects Gladinet CentreStack and TrioFox products prior to version 16.12.10420.56791. Threat actors—including the known ransomware group Clop—are confirmed to have already exploited these vulnerabilities to gain access to organizations’ systems.
Prior to its patching, attackers linked to the Clop ransomware operation were already exploiting CVE-2023-34362 as a zero-day vulnerability. | Earlier this year it was responsible for exploiting a zero-day vulnerability (CVE-2023-0669) in the GoAnywhere MFT platform.
The campaign exploits multiple remotely accessible vulnerabilities patched by Oracle in its July 2025 Critical Patch Update (notably CVE-2025-30745, CVE-2025-30746, and CVE-2025-50107).
The campaign exploits multiple remotely accessible vulnerabilities patched by Oracle in its July 2025 Critical Patch Update (notably CVE-2025-30745, CVE-2025-30746, and CVE-2025-50107).
The campaign exploits multiple remotely accessible vulnerabilities patched by Oracle in its July 2025 Critical Patch Update (notably CVE-2025-30745, CVE-2025-30746, and CVE-2025-50107).
CVE-2022-31199 Cisco Talos was able to link CVE-2022-31199, a vulnerability in Netwrix Auditor, to Truebot activity (and eventually Clop ransomware)... To our knowledge, there is no public exploit for this vulnerability. | “Ransomware (e.g Clop)” and later “...linked CVE-2022-31199... to Truebot activity (and eventually Clop ransomware)”
Groups observed using it
6 distinct threat actors attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
The most notorious among these are campaigns involving banking Trojans such as Dridex and TrickBot, ransomware such as Clop/Cryptomix and MINEBRIDGE...
Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
Cl0p Ransomware, aka Cl0p, is a ransomware group that emerged in February 2019 and targeted most industries worldwide, including retail, transportation, education, manufacturing, automotive, energy, financial, telecommunications and even healthcare.
Microsoft has linked the Clop ransomware gang to recent attacks exploiting a zero-day vulnerability in the MOVEit Transfer platform to steal data from organizations.
Prior to its patching, attackers linked to the Clop ransomware operation were already exploiting CVE-2023-34362 as a zero-day vulnerability.
DefenderDetection ... default: Win32/Clop|Win32/TurtleLoader
Techniques & procedures
25 distinct techniques documented for this family, organized by ATT&CK tactic.
Initial Access
5 techniquesvictims failing to meet their ransom demands are promptly ‘named and shamed’ on ‘CL0P^_- LEAKS’, the group’s Tor-hosted leak site... CL0P provide multiple contact email addresses as well as, more recently, a link to an online chat feature on their Tor hidden service
On May 31st, Progress Software issued an advisory and patch for a vulnerability subsequently identified as CVE-2023-34362 ... The company stated the vulnerability “could lead to escalated privileges and potential unauthorized access to the environment.” ... it later emerged had been happening since at least May 27th.
Whist CL0P are thought to make use of broad malicious email (malspam) campaigns to identify potential corporate victims... In the case of malspam campaigns, the group are thought to send their initial lures during the working week.
CL0P malspam campaigns have been observed as using data stolen from existing victims. As such, customers, partners or vendors of any victim organization could potentially be targeted with incredibly convincing email lures, especially if the group were to infiltrate and send malicious email lures from the original victim’s email server.
Execution
1 techniqueDuring the 2016 Ukraine Electric Power Attack, Sandworm Team used the xp_cmdshell command in MS-SQL. During the 2025 Poland Wiper Attacks, the adversaries leveraged PsExec to run cmd.exe commands on multiple victim machines. Numerous malware families and groups are described as using cmd.exe, cmd /c, Windows command shell, or command-line interfaces to execute commands, payloads, reconnaissance, persistence, cleanup, and ransomware actions.
Persistence
3 techniquesThe content repeatedly describes threat actors and malware modifying, creating, deleting, or storing data in Windows Registry keys and values for persistence, configuration storage, defense evasion, credential access, privilege escalation, and execution.
victims failing to meet their ransom demands are promptly ‘named and shamed’ on ‘CL0P^_- LEAKS’, the group’s Tor-hosted leak site... CL0P provide multiple contact email addresses as well as, more recently, a link to an online chat feature on their Tor hidden service
Privilege Escalation
2 techniquesLimited controls, which allowed the attacker to escalate their privileges to admin after gaining an initial foothold on the network
Stealth
2 techniquesThe content repeatedly describes malware and threat actors decoding, decrypting, or deobfuscating payloads, strings, configuration data, commands, and C2 traffic prior to execution or use, e.g., 'APT28 macro uses the command certutil -decode to decode contents of a .txt file storing the base64 encoded payload' and 'Action RAT can use Base64 to decode actor-controlled C2 server communications.'
Defense Impairment
2 techniquesThe content repeatedly describes threat actors and malware modifying, creating, deleting, or storing data in Windows Registry keys and values for persistence, configuration storage, defense evasion, credential access, privilege escalation, and execution.
The content repeatedly describes threat actors and malware using valid, stolen, forged, self-signed, or abused code-signing certificates to sign malware and appear legitimate, including examples such as AppleJeus using a valid digital signature from Sectigo, APT41 leveraging code-signing certificates, FIN7 signing Carbanak payloads, and SUNBURST being digitally signed by SolarWinds.
Discovery
2 techniquesThe content repeatedly describes malware and threat actors obtaining lists of running processes, using utilities such as tasklist, ps, WMI, Get-Process, CreateToolhelp32Snapshot, EnumProcesses, and similar APIs/commands to enumerate active processes on victim systems.
Avaddon checks for specific keyboard layouts and OS languages to avoid targeting Commonwealth of Independent States (CIS) entities... Bazar can perform a check to ensure that the operating system's keyboard and language settings are not set to Russian... Clop has checked the keyboard language using the GetKeyboardLayout() function... Ryuk has been observed to query the registry key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Nls\Language and the value InstallLanguage.
Collection
3 techniquesthe exfiltration of sensitive and valuable data prior to encryption... In addition to the wholesale theft of data from file servers and network storage devices... CL0P have repeatedly demonstrated their ability to gather large data stores including those used by database and email servers.
they published a raft of stolen documents, from passport scans and driver's licenses to screenshots of software user interfaces. They claimed to have more than 5TB of data taken from the victim organization
CL0P have repeatedly demonstrated their ability to gather large data stores including those used by database and email servers.
Exfiltration
3 techniquesIn late May 2023, data started to be transferred from hundreds of MOVEit deployments, however, these were not normal file transfers initiated by legitimate users. MOVEit had been hacked and the data was being stolen by a ransomware operation called Cl0p.
they acted responsibly by not encrypting their data and only exfiltrating 5TB from the compromised systems
MOVEit had been hacked and the data was being stolen by a ransomware operation called Cl0p... they have increasingly switched to a smash-and-grab, exfiltration-only strategy, relying on the threat of releasing stolen data as leverage to extort payment.
Impact
5 techniquesencrypt the data using the Windows CryptoAPI and then writing this encrypted data to a new file before the original is deleted.
Google has confirmed that the Cl0p ransomware group has successfully exfiltrated large volumes of data from multiple victim environments since August 2025.
The earliest iteration we identified of the shared kill list was a batch script deployed alongside LockerGoga... Other iterations of the list we have observed are also hardcoded directly into the ransomware binaries.
Akira will delete system volume shadow copies via PowerShell commands. Avaddon deletes backups and shadow copies using native system tools. Babuk has the ability to delete shadow volumes using vssadmin.exe delete shadows /all /quiet. BlackCat can delete shadow copies using vssadmin.exe delete shadows /all /quiet and wmic.exe Shadowcopy Delete; it can also modify the boot loader using bcdedit /set {default} recoveryenabled No.
following a supposed collapse in the negotiations of the ransom payment, the actors published the first sample of stolen data
Other
2 techniquesThe content repeatedly describes threat actors and malware disabling or modifying security tools, EDR/AV, logging, firewall rules, integrity checkers, and security settings; e.g., 'Agrius used several mechanisms to try to disable security tools' and 'BlackByte disabled security tools such as Windows Defender and the Raccine anti-ransomware tool during operations.'
Examples include 'Aquatic Panda has attempted to stop endpoint detection and response (EDR) tools', 'BlackByte disabled security tools such as Windows Defender', 'Scattered Spider has uninstalled and disabled security tools', and many malware families terminating AV/EDR processes or services.
IOCs tracked for this family
178 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
IPs, domains, and DNS infrastructure linked to this family.
File hashes (MD5, SHA-1, SHA-256) from samples and reports.
Other indicator types observed in public reporting.
Recent activity
200 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Ransomware family used by the Cl0p group; in this incident it was tied to a long-term intrusion culminating in large-scale data exfiltration and publication of stolen data on Cl0p’s Tor leak site.
A ransomware operation noted here for mass-exploitation campaigns whose victim distribution mirrors the installed base of exploited enterprise software, including Cleo and Oracle EBS-related campaigns.
Cl0p is described as the ransomware responsible for the 2022 attack against South Staffordshire Water, involving long-term intrusion, data theft, and subsequent online leakage of more than 4 TB of company data.
Described as ransomware with conventional mechanics including encryption and double-extortion.
The version that knows your environment.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.