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Clop, also written Cl0p, is a ransomware and extortion operation active since 2019 and widely associated with the cybercrime clusters FIN11 and TA505; some reporting also links the brand to GRACEFUL SPIDER and Lace Tempest. It has targeted organizations across many sectors worldwide, including financial services, manufacturing, retail, transportation, education, telecommunications, energy, automotive, and healthcare. Clop is notable for combining conventional ransomware behavior with large-scale data-theft extortion and for repeatedly exploiting zero-day vulnerabilities in managed file transfer and enterprise software platforms.
Clop has been linked to mass exploitation campaigns against Accellion FTA, GoAnywhere MFT, MOVEit Transfer, SolarWinds Serv-U, Cleo software, and Oracle E-Business Suite. In multiple campaigns, the operation emphasized theft of sensitive data and delayed extortion over immediate encryption, making it one of the more prominent examples of ransomware actors shifting toward pure or primarily exfiltration-based extortion. Victims are commonly pressured through leak-site publication and double-extortion tactics.
On Windows, Clop has demonstrated typical ransomware impact behavior, including encrypting files, deleting shadow copies, and disabling recovery options. Reported defense-evasion features include uninstalling or disabling security products, enumerating security software by process name, modifying the Windows Registry, and geofencing execution by checking keyboard layout and character set to avoid infecting systems configured for Russian or other CIS languages. Clop activity has also been associated with lateral movement using stolen credentials and broader post-compromise operations prior to ransomware deployment.
A Linux ELF variant has also been observed, showing that the operation can target Linux environments in addition to Windows. That variant used similar encryption logic to the Windows branch but appeared less mature and contained implementation flaws that enabled decryption without ransom payment. The existence of both Windows and Linux variants aligns with Clop’s focus on enterprise servers and high-value environments.
Overall, Clop is best characterized as a major ransomware-extortion threat actor and malware family distinguished by opportunistic mass exploitation of high-impact vulnerabilities, strong emphasis on data exfiltration, and broad targeting of enterprise organizations worldwide.
Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.
21 CVEs Mallory has correlated with this family across public research and vendor advisories. Each row links to the full Mallory page for that vulnerability.
Vulnerable Oracle products have been heavily targeted in the past, with a critical Oracle EBS flaw patched in October 2025, tracked as CVE-2025-61882, subjected to attacks by the Clop ransomware gang.
A critical vulnerability in Oracle E-Business Suite (EBS), tracked as CVE-2026-46817 (CVSS 9.8), is being actively exploited in the wild. The flaw resides in the File Transmission component of Oracle Payments and allows an unauthenticated attacker with HTTP network access to take over vulnerable systems.
TA505 (Clop) is one of the oldest groups, active since 2019... It has been exploiting the Cleo zero-day vulnerability (CVE-2024–55956) since late 2024, which makes it the most active of all groups in the first half of 2025.
ICYMI: Catch-up on events relating to the MOVEit data breach so far: ... MOVEit Data Breach [CVE-2023-34362]
Oracle published a security advisory about a vulnerability (CVE-2026-35273) in PeopleSoft, specifically in the Enterprise PeopleTools, versions 8.61 and 8.62. There is credible intelligence that this vulnerability is being actively exploited in the wild, however there is no publicly available proof-of-concept (PoC).
A remote code execution vulnerability (CVE-2021-35211) affecting SolarWinds Serv-U software has previously been exploited as a zero-day by suspected Chinese attackers for cyber espionage purposes, and later by the Cl0p ransomware outfit.
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.
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 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.
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.
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.
8 distinct threat actors attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
the Oracle EBS platform has been under sustained, documented attack by the Cl0p ransomware group and suspected FIN11 operators throughout 2025 and into 2026
the Oracle EBS platform has been under sustained, documented attack by the Cl0p ransomware group and suspected FIN11 operators throughout 2025 and into 2026
Given that the GRACEFUL SPIDER threat group (operating as Cl0p) already demonstrated mass exploitation of a structurally similar Oracle EBS flaw last year... Google Cloud/Mandiant separately confirmed Cl0p ransomware gang involvement in a large scale extortion campaign.
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.
24 distinct techniques documented for this family, organized by ATT&CK tactic.
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
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.
During 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.
During the 2015 Ukraine Electric Power Attack, Sandworm Team modified in-registry Internet settings to lower internet security before launching rundll32.exe ... AADInternals can modify registry keys ... ADVSTORESHELL is capable of setting and deleting Registry values ... [many additional examples].
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
Then by using the RC4 “master-key” the ransomware encrypts the generated RC4 key and stores it to $filename.$clop_extension.
During the 2015 Ukraine Electric Power Attack, Sandworm Team modified in-registry Internet settings to lower internet security before launching rundll32.exe ... AADInternals can modify registry keys ... ADVSTORESHELL is capable of setting and deleting Registry values ... [many additional examples].
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.
Initially, the ransomware creates a new process by calling fork and exits the parent-process. The child-process sets its file mode creation mask... It then calls setsid, creates a session and sets the process group ID.
The content repeatedly describes malware and threat actors listing files and directories, enumerating drives, searching for files by extension/name/path, retrieving file metadata, and browsing file systems (for example: "APT28 has used Forfiles to locate PDF, Excel, and Word documents during collection" and "cmd can be used to find files and directories with native functionality such as dir commands").
It tries to access root by changing the working directory to “/” (chdir(“/”)). Once the permissions are set, the ransomware proceeds encrypting other directories.
Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment.
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.
the 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.
encrypt the data using the Windows CryptoAPI and then writing this encrypted data to a new file before the original is deleted.
The notorious Clop ransomware group attempted to extort dozens of victims after it exploited a zero-day and other vulnerabilities in Oracle E-Business Suite last year.
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.
196 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.
200 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Ransomware family mentioned as part of Deutsche Bank's prior security incidents, not the main incident discussed.
A ransomware family referenced for its mass exploitation activity that inflated Q1 2025 victim counts.
Ransomware family associated here with mass exploitation of Oracle E-Business Suite via CVE-2025-61882 and subsequent large-scale data exfiltration and publication on its leak site.
Ransomware/extortion operation referenced as having been involved in mass exploitation and extortion activity targeting Oracle E-Business Suite vulnerabilities.
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.