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RansomHub: An Emerging Ransomware-as-a-Service

Combating Ransomware

Threat Actors

Since first emerging in February 2024, ransomware-as-a-service (RaaS) group RansomHub has added over 75 victims to its data leak site (DLS). Believed by the intelligence community to be a rebrand of the short-lived “Knight” ransomware group, RansomHub has already made a more significant impact than its alleged predecessor, based on the number of victims and high-profile targets. Recently, RansomHub was observed exploiting the Windows ZeroLogon vulnerability (CVE-2020-1472) for initial access into victim environments. 

The Knight Ransomware Connection 

Many intelligence communities believe RansomHub is a rebrand of Knight ransomware, which may be correct. However, there is an interesting timeline that paints the possibility of an alternate scenario. 

  • Advertisements for the RansomHub RaaS began in the cyber underground on February 2. They cited an encryptor written in the C++ and Go programming languages and offered adjustable encryption algorithms based on affiliate requirements. A new DLS showcasing the RansomHub brand accompanied the dark web advertisements. 

  • The Knight ransomware source code was listed for sale on the underground RAMP forum on February 18, 2024. 

  • The source code is believed to have been sold two days later, on February 20, to an unknown buyer. 

  • RansomHub listed the first victim on its DLS on February 21, one day after the believed sale of the Knight ransomware source code. 

While Arete cannot say for sure whether the threat actors behind RansomHub are the same as those behind Knight ransomware, we are certain that the RansomHub encryptor is based on the Knight ransomware source code. Considering the above timeline, the two most plausible hypotheses are that the actors behind Knight ransomware were waiting to sell their source code before officially launching the rebrand or that the actors behind RansomHub immediately began leveraging their recently purchased encryption capability to target victims in the wild. 

Victimology 

Since its emergence, RansomHub has targeted several high-profile targets and caused a broad impact across multiple sectors: 

  • Frontier: RansomHub extorted telecom giant Frontier and threatened to release 750,000 social security numbers from its customer base. 

  • Christie’s: RansomHub extorted the auction house for the wealthy with the threat of releasing data on 45,000 clients. 

  • Change Healthcare: Following a data security incident, RansomHub attempted to sell PHI stolen from the healthcare giant on the dark web. 

These incidents demonstrate that RansomHub doesn’t shy away from “big game hunting” or sensitive sectors amidst the recent wave of law enforcement actions against ransomware groups. They also showcase that the group is opportunistic when it comes to monetizing its efforts. Most ransomware groups will not invest the time or effort to sell data on the dark web in favor of simply demanding ransoms from their victims. However, RansomHub took the approach of selling the allegedly stolen data from Change Healthcare.  

Should the actors behind RansomHub prove to be the same as those behind Knight ransomware, it should be noted that Knight’s tenure in cybercrime was short lived, as the group was only active for seven months before the source code was listed for sale on RAMP forums.

While not certain, the intent of a hasty exit and rebrand could explain the motivation behind the group’s bold targeting of victims. 

Analyst Comments 

Regardless of the threat actors behind the operation or how long the group will remain active, RansomHub is currently one of the most prolific cybercrime groups active in the threat landscape. The group has targeted a wide range of high-profile victims in its short tenure thus far, and the actors are clearly not afraid to monetize their efforts in any way possible. Arete will continue monitoring for any change of tactics, dark web chatter, or the indication of a possible rebrand for the group. 

Sources 

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CMS Vulnerability Leads to ClickFix Campaign

Threat actors compromised at least 700 education and technology websites in a recent ClickFix campaign by exploiting a critical SQL injection flaw (CVE-2026-26980) in the Ghost content management system (CMS). Adversaries combined the vulnerability with the ClickFix social engineering tactic to steal admin keys and inject a malicious JavaScript that delivers a fake Cloudflare or CAPTCHA verification pop-up, tricking victims into copying and pasting a malicious command into their systems.

What’s Notable and Unique

  • Rather than targeting the end user first, this campaign is unique in its initial exploitation of the system, followed by social engineering attempts. This hybrid attack style is likely being leveraged to bypass traditional defenses.

  • This recent campaign also highlights how trusted web properties can be weaponized at scale and coupled with unpatched CMS vulnerabilities. Rather than using the CMS compromise to perpetrate a single attack, threat actors turned it into a supply-chain attack that ultimately affected over 700 trusted websites.

Analyst Comments

As network defenders and their tools enhance threat detection capabilities, adversaries increasingly seek methods to bypass these defenses. By combining vulnerability exploitation, social engineering techniques, and staging for ancillary attacks, this campaign successfully bypassed traditional defenses and inflicted significant impact. Defending against hybrid cyberattacks requires comprehensive security controls beyond simply patching vulnerabilities. Organizations should focus on limiting movement within the environment, detecting abuse of trusted applications, and preventing end-user manipulation.

Sources

  • 700+ education and tech websites hijacked in huge ClickFix malware campaign

  • Under the engineering hood: Why Malwarebytes chose WordPress as its CMS

  • Think before you Click(Fix): Analyzing the ClickFix social engineering technique

  • Ghost CMS Vulnerability Exploited to Infect 700 Sites With ClickFix Malware

Article

Threat Actors Leverage Fake JPEG Files for Initial Access

In a recent campaign, researchers observed threat actors using fake JPEG image files as a delivery mechanism to initiate the deployment of additional malicious components. The false JPEG files are typically distributed via phishing emails or other social engineering-based lures, and are actually PowerShell-based malware that deploys a trojanized version of ConnectWise ScreenConnect to establish and maintain persistence in the compromised environment. 

What’s Notable and Unique

  • This campaign leverages JPEG images as the initial lure, where the images are not merely decoys but part of the infection workflow. Victims are typically led to download or open an image that triggers hidden execution logic or redirects them to a payload-delivery sequence that initiates later stages of the intrusion chain. 

  • The attack chain is designed to blend into legitimate environments, making detection more difficult. Execution typically relies on scripted or native Windows components, often including PowerShell or other living-off-the-land binaries, enabling fileless or near-fileless execution and reducing forensic artifacts on disk.

  • The multistage design ensures that the initial JPEG does not directly contain the full payload but instead triggers retrieval or decryption steps that progressively assemble the final malicious components in memory.

Analyst Comments

This campaign illustrates how threat actors continue to blur the line between legitimate file handling and malicious execution chains, indicating potential overlap with remote management or administrative tooling. The use of JPEG-based staging combined with script-based execution reflects a broader evolution toward a stealth-first intrusion design, in which file formats serve as triggers rather than payload containers.

Sources

  • OPERATION SILENTCANVAS : JPEG BASED MULTISTAGE POWERSHELL INTRUSION

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