Skip to content
Cyber Threat
CTI Academy Sponsor CTI Academy
Ransomware victim Business Services

cesarcastillo.com

Listed by Clop on · organisation based in Puerto Rico

cesarcastillo.com

Disclosed
Feb 10, 2025
Leak-site listing date
Threat group
Clop
856 victims listed
Country
Puerto Rico
#64 most targeted
Sector
Business Services

ThreatAI analysis

Compiled from this incident record and the threat intelligence profile for Clop. Figures and technique mappings are quoted from the source data, not inferred.

About the Clop group

The ransomware group known as Cl0p is a variant of a previously known strain dubbed CryptoMix. It is worth noting that this variant was delivered as the final payload in a phishing campaign in 2019 and was exclusively financially motivated, with attacks carried out by the threat actors TA505. At that time, malicious actors sent phishing emails that led to a macro-enabled document that would drop a loader called 'Get2.' After gaining an initial foothold in the system or infrastructure, the actors began using reconnaissance, lateral movement, and exfiltration techniques to prepare for the deployment of the ransomware. After the execution of the ransomware, Cl0p appends the extension '.clop' to the end of files, or other types of extensions such as '.CIIp, .Cllp, and .C_L_O_P,' as well as different versions of the ransom note that were also observed after encryption. Depending on the varian Clop has listed 1,302 victims since March 2020.

How Clop is documented to operate

Valid Accounts T1078 Stealth Persistence

Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion. Compromised credentials may be used to bypass access controls placed on various resources on systems within the network and may even be used for persistent access to remote systems and externally available services, such as VPNs, Outlook Web Access, network devices, and remote desktop. Compromised credentials may also grant an adversary increased privilege to specific systems or access to restricted areas of the network.

Mitigations: Application Developer Guidance, User Training, Password Policies, User Account Management, Privileged Account Management, Multi-factor Authentication

MITRE ATT&CK reference
Exploit Public-Facing Application T1190 Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network. The weakness in the system can be a software bug, a temporary glitch, or a misconfiguration. Exploited applications are often websites/web servers, but can also include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other system with Internet-accessible open sockets. On ESXi infrastructure, adversaries may exploit exposed OpenSLP services; they may alternatively exploit exposed VMware vCenter servers.

Mitigations: Vulnerability Scanning, Limit Access to Resource Over Network, Filter Network Traffic, Network Segmentation, Privileged Account Management, Application Isolation and Sandboxing

MITRE ATT&CK reference
Command and Scripting Interpreter T1059 Execution

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell. There are also cross-platform interpreters such as Python, as well as those commonly associated with client applications such as JavaScript and Visual Basic.

Mitigations: Restrict Web-Based Content, Limit Software Installation, Execution Prevention, Code Signing, Behavior Prevention on Endpoint, Privileged Account Management

MITRE ATT&CK reference
Native API T1106 Execution

Adversaries may interact with the native OS application programming interface (API) to execute behaviors. Native APIs provide a controlled means of calling low-level OS services within the kernel, such as those involving hardware/devices, memory, and processes. These native APIs are leveraged by the OS during system boot (when other system components are not yet initialized) as well as carrying out tasks and requests during routine operations. Adversaries may abuse these OS API functions as a means of executing behaviors.

Mitigations: Execution Prevention, Behavior Prevention on Endpoint

MITRE ATT&CK reference
User Execution T1204 Execution

An adversary may rely upon specific actions by a user in order to gain execution. Users may be subjected to social engineering to get them to execute malicious code by, for example, opening a malicious document file or link. These user actions will typically be observed as follow-on behavior from forms of Phishing. While User Execution frequently occurs shortly after Initial Access it may occur at other phases of an intrusion, such as when an adversary places a file in a shared directory or on a user's desktop hoping that a user will click on it. This activity may also be seen shortly after Internal Spearphishing.

Mitigations: Network Intrusion Prevention, Restrict Web-Based Content, Limit Software Installation, User Training, Execution Prevention, Behavior Prevention on Endpoint

MITRE ATT&CK reference

MITRE ATT&CK techniques attributed to Clop across its recorded activity, not a finding about how cesarcastillo.com was reached.

Vulnerabilities Clop is recorded exploiting

6 of these 6 are in the CISA Known Exploited Vulnerabilities catalog, 6 of them recorded by CISA as used in ransomware campaigns. CVEs attributed to Clop across its reported activity. There is no indication that any of these was involved in the cesarcastillo.com incident — the source data does not record an entry point.

Incident analysis

cesarcastillo.com was listed by Clop ransomware, a group with 856 victims recorded in this database. The listing appeared on the group's leak site on February 10, 2025.

cesarcastillo.com is based in Puerto Rico and operates in the Business Services sector. Puerto Rico ranks #64 worldwide for ransomware disclosures, with 21 victims in this database.

Sector context. Business services firms often have access to multiple client environments, making them high-value pivot points for ransomware operators seeking to maximise impact across multiple victim organisations.

Clop typically follows a double extortion model: data is exfiltrated from the victim's systems before files are encrypted, so the victim faces two demands at once — pay to restore access, and pay to keep stolen data unpublished. The leak site, where this listing appeared, is the lever for the second demand.

Source. Public leak-site disclosures aggregated via the ransomware.live API. The disclosure date is when the listing was published, which can differ from the date of compromise. This site does not publish or link to stolen data. Last updated .

Frequently asked questions

Was cesarcastillo.com attacked by ransomware?

Yes. cesarcastillo.com was listed as a victim of the Clop ransomware group on February 10, 2025. The organisation is based in Puerto Rico and operates in the Business Services sector. The disclosure appeared on the group's dark web leak site.

Which ransomware group attacked cesarcastillo.com?

cesarcastillo.com was attacked by Clop ransomware. Clop is one of the most active ransomware groups, having claimed 856 victims globally. The group typically employs a double-extortion model: encrypting the victim's files and threatening to publish stolen data.

When did the cesarcastillo.com ransomware attack occur?

The ransomware attack on cesarcastillo.com was disclosed on February 10, 2025. This date reflects when the victim was published on the threat group's leak site, which may differ from the actual date of initial compromise.

What data was stolen in the cesarcastillo.com ransomware attack?

The specific data stolen from cesarcastillo.com has not been independently verified by this platform. Ransomware groups typically exfiltrate data before encrypting systems and use the threat of publication to pressure victims. As a Business Services organisation, cesarcastillo.com likely held sensitive business data, client information, and operational records.

How can organisations protect against Clop attacks?

To defend against Clop and similar threat actors, organisations should: maintain regular offline backups tested for restoration; implement network segmentation to limit lateral movement; deploy multi-factor authentication on all remote access; use endpoint detection and response (EDR) tools; conduct regular phishing and security awareness training; and monitor threat intelligence feeds for indicators of compromise (IOCs) associated with active groups.