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Understanding Mimic Ransomware: Features, Threats, and Noteworthy Exploits

 


Mimic is a ransomware family first discovered in 2022. Like other ransomware, it encrypts files on a victim’s system and demands a cryptocurrency payment for the decryption key. What makes Mimic particularly concerning is its dual approach: it not only encrypts data but also exfiltrates it beforehand. This stolen data can be used as leverage, with attackers threatening to release or sell it if the ransom is not paid. 
 
Mimic is believed to reuse code from Conti, a well-known ransomware whose source code was leaked after the group publicly supported Russia’s invasion of Ukraine. While the exact origins of Mimic remain unclear, its operations appear to primarily target English- and Russian-speaking users.   
 

Exploitation of Legitimate Tools  

 
One of Mimic’s distinctive features is its exploitation of the API from Everything, a legitimate Windows file search tool developed by Voidtools. By leveraging this tool, the ransomware can quickly locate and encrypt files, increasing the efficiency of its attacks.   
 
Importantly, Mimic does not rely on victims having Everything pre-installed. Instead, it typically packages the tool along with additional malicious programs designed to:   
 
  • Disable Windows Defender to reduce system defenses. 
  • Misuse Sysinternals’ Secure Delete tool to erase backups, making file recovery more difficult. 

Indicators of Infection  

 
Victims of Mimic can identify an infection by the “.QUIETPLACE” extension added to encrypted files. Additionally, the ransomware leaves a ransom note demanding $3,000 in cryptocurrency to provide the decryption key.   
 
In many cases, victims feel compelled to pay the ransom, particularly when backups have been deleted or compromised.   
 

The Emergence of Elpaco   

 
A new variant of Mimic, known as Elpaco, has recently been detected. This variant is associated with attacks that involve brute-forcing Remote Desktop Protocol (RDP) credentials. Once access is gained, attackers exploit the *Zerologon* vulnerability (CVE-2020-1472) to escalate privileges and deploy the ransomware.   
 
Reports of Elpaco infections have surfaced in countries such as Russia and South Korea, underscoring the expanding reach and evolving capabilities of this ransomware family.   
 

The Importance of Vigilance 

 
Although tools like Everything and Secure Delete are not inherently harmful, Mimic’s misuse of these legitimate programs highlights the need for continuous vigilance. Cybercriminals are increasingly finding ways to exploit trusted software for malicious purposes. 
 
As Mimic and its variants continue to evolve, implementing robust cybersecurity measures—including regular system updates, strong authentication protocols, and comprehensive backup strategies—remains essential to mitigating the risk of ransomware attacks.

Threat Actors are Still Exploting Old Bugs to Target Organizations

 

Cybersecurity researchers at Qualys have published a free ransomware risk and assessment tool designed to scan systems, identify flaws and finally automate patching and remediation.

Researchers at Qualys analyzed 36 leading ransomware families and their attacks in recent years. It was found that unpatched flaws, device misconfigurations, internet-facing assets, and cracked software were consistently ranked among the top attack vectors.

According to researchers, the top five CVEs exploited by leading ransomware families to target organizations worldwide, have been known for almost a decade and had vendor patches available. But because many organizations still haven't applied the available security updates, they remain susceptible to ransomware attacks. 

CVE-2012-1723, is the oldest of the top five vulnerabilities, a flaw in the Java Runtime Environment (JRE) component in Oracle Java SE 7, detailed in 2012. According to researchers, it's been commonly used to distribute Urausy ransomware. 

The other two other common flaws detailed by researchers are from 2013; CVE-2013-0431 is a vulnerability in JRE leveraged by Reveton ransomware, while CVE-2013-1493 is a vulnerability in Oracle Java that is exploited by Exxroute ransomware. In both cases, security updates have been available for more than eight years.

CVE-2018-12808, on the other hand, is a three-year-old bug in Adobe Acrobat, which is used to deliver ransomware via phishing emails and malicious PDF files. Both Ryuk ransomware and Conti ransomware have been known to use this attack method. The latest bug on the list is Adobe CVE-2019-1458, a privilege escalation flaw in Windows that appeared in December 2019 and has been commonly used by the NetWalker ransomware group.

“For IT and information security teams, applying all the patches needed to keep a network secure is often an uphill battle. The rate at which vulnerabilities are rising is exponentially higher than the rate at which operations teams are patching. This is the number one driving factor for why vulnerabilities remain unpatched It is easy for operations teams to get overwhelmed when they do not have a prioritized list of patches or software listings provided from security teams," Shailesh Athalye, SVP of product management at Qualys, stated. 

Threat actors exploit these flaws because they know many organizations don’t pay attention to the security updates and so they are actively searching for flaws that allow them to lay down the foundations for ransomware attacks.

"There is no silver bullet to prevent ransomware and remediate vulnerabilities, but overall, driving processes for reducing an attack surface should be the goal. The important part of vulnerability management is the combination of vulnerability assessment, prioritization, and remediation," Athalye further told.