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FBI Warns of Silent Ransom Group Using Phishing and Vishing to Target U.S. Law Firms

 

The FBI has issued a warning about a sophisticated cybercriminal group known as the Silent Ransom Group (SRG), also referred to by aliases like Luna Moth, Chatty Spider, and UNC3753. This group has been actively targeting U.S.-based law firms and related organizations through advanced phishing techniques and social engineering scams. The group, which has been operational since 2022, is known for using deceptive communication methods to gain unauthorized access to corporate systems and extract sensitive legal data for ransom demands. In the past, SRG’s activities spanned across industries such as healthcare and insurance. 

However, since the spring of 2023, its focus has shifted to legal entities, likely because of the highly confidential nature of the data managed by law firms. The group commonly uses a method called callback phishing, also known as reverse vishing. In this approach, victims receive emails that appear to originate from reputable companies and warn them of small charges for fake subscriptions. The emails prompt users to call a phone number to cancel the subscription. During these calls, victims are instructed to download remote access software under the guise of resolving the issue. Once the software is installed, SRG gains control of the victim’s device, searches for valuable data, and uses it to demand ransom.  

In March 2025, SRG has adapted their strategy to include voice phishing or vishing. In this new approach, the attackers call employees directly, posing as internal IT staff. These fraudulent callers attempt to convince their targets to join remote access sessions, often under the pretext of performing necessary overnight maintenance. Once inside the system, the attackers move swiftly to locate and exfiltrate data using tools like WinSCP or a disguised version of Rclone. Notably, SRG does not prioritize escalating privileges, instead focusing on immediate data theft. The FBI noted that these voice phishing methods have already resulted in multiple successful breaches. 

SRG reportedly continues to apply pressure during ransom negotiations by making follow-up calls to victim organizations. While the group does maintain a public site for releasing stolen data, its use of this platform is inconsistent, and it does not always follow through on threats to leak information. A significant concern surrounding these attacks is the difficulty in detection. SRG uses legitimate system management and remote access tools, which are often overlooked by traditional antivirus software. The FBI advises organizations to remain vigilant, particularly if there are unexplained downloads of programs such as AnyDesk, Zoho Assist, or Splashtop, or if staff receive unexpected calls from alleged IT personnel. 

In response, the FBI urges companies to bolster cybersecurity training, establish clear protocols for authenticating internal IT requests, and enforce two-factor authentication across all employee accounts. Victims of SRG attacks are encouraged to share any information that might assist in ongoing investigations, including ransom communications, caller details, and cryptocurrency wallet data.

Scattered Spider Cyberattack Cripples M&S, Co-op: DragonForce Ransomware Causes Weeks-Long Disruption

 

Weeks after a significant cyberattack disrupted operations at major British retailers, companies like Marks & Spencer (M&S) and Co-op are still struggling to restore full functionality. Despite public reassurances, the scope of the attack is proving more serious than initially acknowledged. M&S CEO Stuart Machin recently confirmed that personal customer data had been accessed, prompting the company to require password resets for online accounts. Online orders on the M&S website remain suspended weeks after the breach, and no clear timeline has been offered for full recovery. 

The attack first became public on April 25 when M&S halted its online operations due to a cyber intrusion. Within days, Co-op revealed it had also been targeted in an attempted hack, which disrupted several services. Harrods, another luxury retailer, was also reportedly affected during this wave of cyberattacks. While M&S is still unable to process online sales, Co-op has only just resumed stocking its shelves, and both companies remain silent about when operations might return to normal. Government officials have weighed in on the seriousness of the incident. 

Cabinet Office Minister Pat McFadden called the attack a “wake-up call” for British businesses, highlighting the urgent need for enhanced cybersecurity protocols. Financial losses have been steep. M&S is reportedly losing £3.5 million per day while its website remains offline, and its stock has dropped by an estimated half a billion pounds in market value. Co-op also disclosed that customer data had been compromised, and they experienced issues with card payments at the height of the disruption. 

Investigations suggest the cybercriminal group known as Scattered Spider is responsible. Known for targeting large enterprises, the group is believed to have used a ransomware strain called DragonForce to paralyze systems. According to cybersecurity experts, the attackers may have exploited unpatched vulnerabilities and misconfigured systems to gain entry. Reports indicate they employed SIM-swapping tactics to hijack phone numbers and impersonate employees, fooling IT help desks into granting system access. Once inside, the hackers are believed to have compromised Microsoft Active Directory—a central hub that connects internal networks—potentially gaining access to crucial files and passwords. 

Though it’s unlikely they decrypted these password files directly, the level of access would have allowed them to severely disrupt internal systems. Experts say this level of infiltration can cripple multiple areas of a business, making recovery extremely challenging without a full rebuild of core IT infrastructure. One reason for the prolonged disruption may be that both M&S and Co-op chose not to pay the ransom, in line with UK government advice. While this decision aligns with best practices to avoid funding cybercrime, it also means recovery will take significantly longer. 

Despite the chaos, M&S has emphasized that no payment information or account passwords were compromised. The company is urging customers to reset their passwords for peace of mind and has provided guidelines on staying safe online. Co-op has resumed deliveries to most of its stores but acknowledged that some shelves may still lack regular stock. Empty shelves and apology signs have appeared across affected stores, as customers share their frustrations online. 

This incident underscores the growing threat posed by sophisticated cybercriminals and the urgent need for companies to prioritize cybersecurity. From exploiting human error to using advanced ransomware tools, the tactics are evolving, and so must the defenses.

Employee Monitoring Tool Kickidler Targeted in Ransomware Attacks

 

Cybersecurity researchers have discovered that cybercriminals are misusing a legitimate employee monitoring tool called Kickidler to execute targeted ransomware attacks. Originally developed to help businesses track productivity and ensure compliance, Kickidler offers features like real-time screen monitoring, keystroke logging, and activity tracking—functionalities that have now become attractive tools for threat actors. Security firms Varonis and Synacktiv have reported observing these attacks actively taking place. 

The attack campaign begins with malicious advertisements placed on the Google Ads network. These ads are cleverly designed to trick users searching for a legitimate utility called RVTools—a free Windows application used to connect to VMware vCenter or ESXi environments. Victims are lured into downloading a trojanized version of RVTools, which secretly installs a backdoor named SMOKEDHAM. Once SMOKEDHAM gains access to the system, attackers use it to deploy Kickidler, with a focus on targeting enterprise administrators. 

By infiltrating admin machines, the attackers can monitor keystrokes and capture sensitive data, such as credentials for off-site backups or cloud platforms. This method allows them to bypass more secure authentication systems that are often separated from Windows domains, a common defense strategy in many organizations. According to the researchers, the ransomware groups Qilin and Hunters International have been leveraging this approach to expand their reach within enterprise networks. 

These groups appear to be focusing on cloud backup systems and VMware ESXi infrastructure. Hunters International, in particular, was observed using VMware PowerCLI and WinSCP Automation tools to enable SSH access, deploy ransomware, and execute it on ESXi servers. Their payloads encrypted VMDK virtual hard disks, disrupting operations and access to virtual environments. 

One of the most concerning aspects of this campaign is how stealthily it operates. By capturing data directly from administrators’ screens and inputs, the attackers avoid using higher-risk tactics like memory dumps or privilege escalation, which are more likely to be flagged by security systems. The misuse of Kickidler demonstrates a growing trend of cybercriminals weaponizing legitimate enterprise tools to bypass traditional defenses and maintain stealth within targeted networks. 

These attacks highlight the need for increased vigilance around software downloads, especially from third-party sources, and reinforce the importance of strong endpoint protection, regular software audits, and employee awareness training. 

As cyberattacks grow more sophisticated, defenders must adapt by tightening controls, decoupling critical system access from everyday credentials, and monitoring for unusual activity—even from tools considered safe.

Windows CLFS Zero-Day CVE-2025-29824 Exploited by Ransomware Group Storm-2460

 

A newly disclosed Windows zero-day vulnerability, tracked as CVE-2025-29824, is being actively exploited in cyberattacks to deliver ransomware, Microsoft has warned. This flaw affects the Windows Common Log File System (CLFS) driver and enables local privilege escalation—a method often used by attackers after gaining initial access. 

Microsoft’s Threat Intelligence and Security Response teams revealed that the bug is classified as a “use-after-free” vulnerability with a severity score of 7.8. While attackers need to compromise a system before they can exploit this flaw, it remains highly valuable in ransomware operations. Cybercriminals often rely on these types of vulnerabilities to turn a limited foothold into full administrative control across networks. 

The cybercrime group currently leveraging this zero-day is known as Storm-2460. Microsoft reports that the group is using the exploit to deploy a custom backdoor named PipeMagic, which in turn facilitates the installation of RansomEXX ransomware—a variant not commonly observed but still capable of serious disruption. So far, Storm-2460 has targeted organizations in industries such as IT, finance, and retail, with victims located in countries including the United States, Spain, Saudi Arabia, and Venezuela. 

Microsoft emphasized that the number of known cases remains small, but the sophistication of the exploit is concerning. This attack is notable for being part of a “post-compromise” campaign, meaning the attacker already has a presence within the system before using the flaw. These types of exploits are frequently used to escalate privileges and move laterally within a network, eventually leading to broader ransomware deployment. Microsoft issued a security advisory for CVE-2025-29824 on April 8 and urged organizations to install updates immediately. Failure to do so could leave critical systems vulnerable to privilege escalation and full network compromise. 

To mitigate risk, Microsoft advises businesses to prioritize patch management, restrict unnecessary administrative privileges, and closely monitor for unusual behavior across endpoints. Cybersecurity teams are also encouraged to review logs for any indicators of compromise related to PipeMagic or RansomEXX. As ransomware tactics continue to evolve, the exploitation of vulnerabilities like CVE-2025-29824 reinforces the need for proactive defense strategies and rapid incident response protocols.

FBI Warns Against Fake Online Document Converters Spreading Malware

 

iThe FBI Denver field office has issued a warning about cybercriminals using fake online document converters to steal sensitive data and deploy ransomware on victims' devices. Reports of these scams have been increasing, prompting authorities to urge users to be cautious and report incidents.

"The FBI Denver Field Office is warning that agents are increasingly seeing a scam involving free online document converter tools, and we want to encourage victims to report instances of this scam," the agency stated.

Cybercriminals create fraudulent websites that offer free document conversion, file merging, or media download services. While these sites may function as expected, they secretly inject malware into downloaded files, enabling hackers to gain remote access to infected devices.

"To conduct this scheme, cybercriminals across the globe are using any type of free document converter or downloader tool," the FBI added.

These sites may claim to:
  • Convert .DOC to .PDF or other file formats.
  • Merge multiple .JPG files into a single .PDF.
  • Offer MP3 or MP4 downloads.
Once users upload their files, hackers can extract sensitive information, including:
  • Names and Social Security Numbers
  • Cryptocurrency wallet addresses and passphrases
  • Banking credentials and passwords
  • Email addresses
Scammers also use phishing tactics, such as mimicking legitimate URLs by making slight alterations (e.g., changing one letter or replacing "CO" with "INC") to appear trustworthy.

“Users who in the past would type ‘free online file converter’ into a search engine are vulnerable, as the algorithms used for results now often include paid results, which might be scams,” said Vikki Migoya, Public Affairs Officer for FBI Denver.

Cybersecurity experts have confirmed that these fraudulent websites are linked to malware campaigns. Researcher Will Thomas recently identified fake converter sites, such as docu-flex[.]com, distributing malicious executables like Pdfixers.exe and DocuFlex.exe, both flagged as malware.

Additionally, a Google ad campaign in November was found promoting fake converters that installed Gootloader malware, a malware loader known for:

  1. Stealing banking credentials
  2. Installing trojans and infostealers
  3. Deploying Cobalt Strike beacons for ransomware attacks

"Visiting this WordPress site (surprise!), I found a form for uploading a PDF to convert it to a .DOCX file inside a .zip," explained a cybersecurity researcher.

Instead of receiving a legitimate document, users were given a JavaScript file that delivered Gootloader, which is often used in ransomware attacks by groups like REvil and BlackSuit.

In order to stay safe,
  • Avoid unknown document conversion sites. Stick to well-known, reputable services.
  • Verify file types before opening. If a downloaded file is an .exe or .JS instead of the expected document format, it is likely malware.
  • Check reviews before using any online converter. If a site has no reviews or looks suspicious, steer clear
  • Report suspicious sites to authorities. Victi
  • ms can file reports at IC3.gov.
  • While not all file converters are malicious, thorough research and caution are crucial to staying safe online.

Betruger Backdoor Linked to RansomHub Ransomware Attacks on Critical Infrastructure

 

A newly discovered backdoor malware, dubbed Betruger, has been identified in multiple recent ransomware attacks. Researchers at Symantec believe at least one affiliate of the RansomHub ransomware-as-a-service (RaaS) operation is using this sophisticated tool to facilitate cyber intrusions. 

Unlike many conventional malware strains, Betruger functions as a multi-purpose backdoor designed to prepare networks for ransomware deployment while minimizing the need for additional malicious software. Betruger comes equipped with several advanced features commonly associated with pre-ransomware attack stages. These include keylogging, network scanning, privilege escalation, credential theft, screenshot capture, and the ability to upload files to a command-and-control (C2) server. 

Its design suggests that attackers are looking to streamline their intrusion process, reducing reliance on multiple external tools and instead using a single, custom-built malware to execute various attack functions. This approach is relatively rare, as ransomware operators typically rely on widely available tools such as Mimikatz and Cobalt Strike to conduct their attacks. To avoid detection, cybercriminals are disguising Betruger under the filenames ‘mailer.exe’ and ‘turbomailer.exe,’ making it appear like a legitimate email-related application. 

While other ransomware groups have developed proprietary tools for data exfiltration, such as BlackMatter’s Exmatter and BlackByte’s Exbyte, Betruger appears to have a broader range of capabilities beyond just stealing data. The emergence of Betruger coincides with ongoing attacks by RansomHub, a ransomware operation that has been active since February 2024. Previously known as Cyclops and Knight, RansomHub has gained a reputation for focusing on extortion through data theft rather than encrypting victim files. 

Over the past year, the group has targeted several major organizations, including Halliburton, Christie’s, Frontier Communications, Rite Aid, and Kawasaki’s EU division. It was also responsible for leaking Change Healthcare’s stolen data after the BlackCat/ALPHV group’s $22 million exit scam. More recently, RansomHub claimed responsibility for breaching BayMark Health Services, a leading addiction treatment provider in North America. 

The company operates over 400 treatment centers across the U.S. and Canada, serving approximately 75,000 patients daily. The FBI has linked RansomHub affiliates to more than 200 ransomware attacks affecting various critical infrastructure sectors in the U.S., including government agencies, healthcare institutions, and other essential services. With the deployment of Betruger, the group’s operations appear to be evolving, indicating a continued threat to businesses and organizations worldwide.

Medusa Ransomware Attacks: CISA, FBI, and MS-ISAC Issue #StopRansomware Advisory

 

The Cybersecurity and Infrastructure Security Agency (CISA), in partnership with the FBI and the Multi-State Information Sharing and Analysis Center (MS-ISAC), has issued a #StopRansomware advisory, warning organizations about the increasing threat of Medusa ransomware. 

Medusa, a ransomware-as-a-service (RaaS) variant, was first detected in 2021 and has since targeted over 300 victims across multiple critical infrastructure sectors. Industries such as healthcare, law, education, insurance, technology, and manufacturing have been particularly affected, highlighting the wide reach and severity of the ransomware’s impact. Medusa initially operated as a closed ransomware variant, meaning its developers had full control over its deployment and operations. 

Over time, it transitioned to an affiliate-based model, allowing external cybercriminals to use the ransomware while keeping certain aspects, such as ransom negotiations, under the control of the original developers. This shift has allowed Medusa to expand its reach, increasing its effectiveness as a cyber threat. Medusa demands ransoms ranging from $100,000 to as much as $15 million. 

Like many modern ransomware variants, it employs double extortion tactics—stealing sensitive data before encrypting victim networks. This strategy puts additional pressure on victims, as attackers can threaten to leak or sell stolen data if the ransom is not paid. Cybersecurity researchers from Symantec’s Threat Hunter team recently reported a rise in Medusa-related attacks over the past year. 

Medusa’s developers use initial access brokers (IABs) to gain entry into victim networks. These brokers operate within cybercriminal forums and marketplaces, selling access to compromised systems for amounts ranging from $100 to $1 million. Medusa affiliates rely on phishing campaigns and vulnerability exploitation to gain initial access, making it crucial for organizations to bolster their email security and patch known vulnerabilities. Once inside a system, Medusa operators use “living-off-the-land” (LotL) techniques, leveraging legitimate system tools to evade detection while conducting reconnaissance, data theft, and lateral movement.

Given Medusa’s evolving tactics, cybersecurity experts stress the importance of proactive defense measures. Organizations should deploy security patches, implement network segmentation, and restrict access to critical services from untrusted sources. Dan Lattimer, area vice president for Semperis in the UK and Ireland, emphasized the need for an “assumed breach” mindset, urging companies to shift from a prevention-focused approach to rapid detection, response, and recovery. 

As ransomware attacks grow more sophisticated, organizations must remain vigilant, continuously updating their cybersecurity strategies to mitigate risks and strengthen their defenses against threats like Medusa.

Turning The Screws: Pressure Techniques Used by Ransomware Outfits

 

Over the past ten years, ransomware attacks have increased in frequency and sophistication. While exploits like social engineering and unpatched software may help with an initial breach, it's the coercive tactics that force victims to make rash and emotionally charged decisions, like paying the ransom. 

Below are three of the most common tactics used by ransomware perpetrators to persuade victims into complying with their extortion demands.

1. Fear and humiliation 

Fear is a potent emotion that threat actors use. When a victim's documents are encrypted, the message is usually clear: pay the ransom or lose your data forever. In addition to the fear of data loss, cybercriminals use the threat of humiliation to demand ransom in order to prevent the disclosure of sensitive information such as company files, financial data, or personal images. 

Cybercriminals sometimes go one step further by threatening legal action, especially in highly regulated sectors like healthcare or finance: Pay the ransom, or we'll denounce you to the authorities. Due to the increased pressure, victims are compelled to take action out of fear about possible legal action. 

2. Deadlines and ultimatums

Most ransomware demands include a tight deadline to intensify the pressure. Attackers usually give victims a deadline, like 48 hours, to comply, frequently along with a clear warning of the repercussions. Some ransomware programs show a countdown meter, which acts as a continual reminder that time is running out, to further exacerbate panic. Attackers may raise the stakes, such as making some of the stolen material publicly available, or double the ransom if the deadline is missed.

3. False hope and fake assurances 

False promises are another tactic used by ransomware operators to trick victims into believing there is a possible solution. However, victims are merely coerced into complying by this hope. Attackers may provide a solution like a trial decryption tool to "prove" their solution works, a discount for speedy payment, or an extension on the payment deadline—tactics intended to strengthen the notion that paying the ransom would result in a complete recovery.

In reality, just 4% of individuals who pay are able to restore all their data. Furthermore, criminals frequently say that if the ransom is paid, the stolen data will be completely destroyed and the victim will be left alone. However, 78% of victims who pay report recurring attacks, proving that these assurances are nothing more than intentional deception. 

Mitigation tips 

The following are some best practices that can help organisations in handling these pressure tactics: 

Preparedness:    Ransomware attacks can happen to anyone. Employers must provide clear instructions and techniques for their employees to follow, as well as teach them how to respond and report in stressful situations while remaining calm and composed. 

Avoiding impulsiveness:  Avoid making decisions primarily based on emotional factors such as anxiousness or desperation. Evaluate all available information and investigate possible solutions and alternatives. 

Not making a payment right away: Don't ever give in to the urge to pay. Speak with law enforcement, cybersecurity experts, and skilled ransomware negotiators, or get advice from cyber insurance companies. Investigate backups and other recovery options. Online decryptors may even be accessible for some ransomware strains.