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Showing posts with label Malware Trojan. Show all posts

Abuse of Cloudflare Tunnel Service for Malware Campaigns Delivering RATs

 

Researchers have raised alarms over cybercriminals increasingly exploiting the Cloudflare Tunnel service in malware campaigns that predominantly distribute remote access trojans (RATs). This malicious activity, first detected in February, utilizes the TryCloudflare free service to disseminate multiple RATs, including AsyncRAT, GuLoader, VenomRAT, Remcos RAT, and Xworm. Cloudflare Tunnel service allows users to proxy traffic through an encrypted tunnel to access local services and servers over the internet without exposing IP addresses. 

This service is designed to offer added security and convenience by eliminating the need to open public inbound ports or set up VPN connections. With TryCloudflare, users can create temporary tunnels to local servers and test the service without requiring a Cloudflare account. However, threat actors have abused this feature to gain remote access to compromised systems while evading detection. A recent report from cybersecurity company Proofpoint observed that malware campaigns are targeting organizations in the law, finance, manufacturing, and technology sectors with malicious .LNK files hosted on the legitimate TryCloudflare domain. The attackers lure targets with tax-themed emails containing URLs or attachments leading to the LNK payload. 

Once launched, the payload runs BAT or CMD scripts that deploy PowerShell, culminating in the download of Python installers for the final payload. Proofpoint reported that an email distribution wave starting on July 11 sent out over 1,500 malicious messages, a significant increase from an earlier wave on May 28, which contained fewer than 50 messages. Hosting LNK files on Cloudflare offers several advantages to cybercriminals, including making the traffic appear legitimate due to Cloudflare’s reputation. 

Additionally, the TryCloudflare Tunnel feature provides anonymity, and the temporary nature of the subdomains makes it challenging for defenders to block them effectively. The use of Cloudflare’s service is not only free and reliable but also allows cybercriminals to avoid the costs associated with setting up their own infrastructure. 

By employing automation to evade blocks from Cloudflare, these criminals can use the tunnels for large-scale operations. A Cloudflare representative stated that the company immediately disables and takes down malicious tunnels as they are discovered or reported by third parties. Cloudflare has also implemented machine learning detections to better contain malicious activity and encourages security vendors to submit suspicious URLs for prompt action. 

In light of this increasing threat, it is crucial for organizations to remain vigilant and enhance their cybersecurity measures to defend against these sophisticated malware campaigns.

North Korean Hacker Group Kimsuky Deploys New Linux Malware 'Gomir' via Trojanized Software Installers

 

North Korean hacker group Kimsuky has unveiled a new Linux malware named "Gomir," a variant of the GoBear backdoor. This development marks a significant advancement in the group's cyber espionage tactics. Kimsuky, linked to North Korea’s military intelligence, the Reconnaissance General Bureau (RGB), has a history of sophisticated cyber attacks aimed primarily at South Korean entities. 

In early February 2024, researchers at SW2, a threat intelligence company, reported a campaign by Kimsuky involving trojanized versions of various software solutions. These included TrustPKI and NX_PRNMAN from SGA Solutions and Wizvera VeraPort. The primary targets were South Korean entities, and the malicious software delivered the Troll Stealer and Go-based Windows malware known as GoBear. 

Further investigation by Symantec, a Broadcom company, revealed that the same campaign also deployed a Linux variant of the GoBear backdoor, dubbed "Gomir." This new malware shares many similarities with its Windows counterpart, featuring direct command and control (C2) communication, persistence mechanisms, and support for executing a wide range of commands. Upon installation, Gomir checks the group ID value to determine if it runs with root privileges on the Linux machine. 

It then copies itself to /var/log/syslogd for persistence, creates a systemd service named ‘syslogd,’ and issues commands to start the service. Following these steps, the original executable is deleted, and the initial process is terminated. To ensure it runs on system reboot, the backdoor attempts to configure a crontab command by creating a helper file ('cron.txt') in the current working directory. If successful, the helper file is removed. Gomir supports 17 operations triggered by commands received from the C2 via HTTP POST requests. 

These operations include pausing communication with the C2 server, executing arbitrary shell commands, reporting the current working directory, probing network endpoints, and more. Notably, these commands are almost identical to those supported by the GoBear Windows backdoor, highlighting the malware's versatility and Kimsuky's ability to adapt its tools across different operating systems. Symantec researchers have pointed out that supply-chain attacks, such as trojanized software installers and fake installers, are a preferred attack method for North Korean espionage actors. 

The choice of software for trojanization seems to be carefully selected to maximize infection rates among South Korean targets. By compromising widely used software solutions, Kimsuky increases its chances of infiltrating targeted systems and exfiltrating valuable data. The implications of Kimsuky's activities are significant. By enhancing their malware capabilities and expanding their target range to include Linux systems, Kimsuky poses a heightened threat to organizations, particularly those in South Korea. 

The use of advanced malware like Gomir demonstrates the group's continuous evolution and sophistication in cyber espionage. Symantec's report on this campaign includes a set of indicators of compromise (IOCs) for multiple malicious tools observed, including Gomir, Troll Stealer, and the GoBear dropper. These IOCs are crucial for cybersecurity professionals to detect and mitigate the impact of these threats. 

As the digital landscape continues to evolve, the need for robust cybersecurity measures becomes ever more critical. Organizations, especially those in high-target regions like South Korea, must remain vigilant and proactive in their defense strategies. This includes regularly updating software, conducting thorough security assessments, and implementing comprehensive threat detection and response mechanisms. 

The emergence of Gomir and similar threats underscores the importance of international cooperation in combating cybercrime. By sharing intelligence and collaborating on cybersecurity initiatives, nations can better protect their critical infrastructure and sensitive data from sophisticated threat actors like Kimsuky.

Hydra Malware Targets Germany's Second Largest Bank Customers

 

The Hydra banking trojan has resurfaced to target European e-banking platform users, especially Commerzbank customers, Germany's second-largest financial institution. 

MalwareHunterTeam discovered the two-year-old virus in a fresh dissemination operation that targets German users with a malicious APK called 'Commerzbank Security' with a lookalike icon to the legitimate application. 

This grabbed the attention of Cyble researchers, who sampled the file for a more in-depth study, revealing a sophisticated phishing tool with broad rights access. 

According to Cyble experts, Hydra is still evolving; the variations used in the latest campaign include TeamViewer features, similar to the S.O.V.A. Android banking Trojan, and utilize various encryption methods to avoid detection, as well as Tor for communication. 

The latest version additionally allows to turn off the Play Protect Android security function. The virus demands two very hazardous permissions, BIND_ACCESSIBILITY_PERMISSION and BIND_DEVICE_ADMIN, according to the experts. 

The Accessibility Service is a background service that assists users with disabilities, and the BIND_ACCESSIBILITY_SERVICE permission permits the app to access it. 

The analysis published by Cyble states, “Malware authors abuse this service to intercept and monitor all activities happening on the device’s screen. For example, using Accessibility Service, malware authors can intercept the credentials entered on another app.” 

“BIND_DEVICE_ADMIN is a permission that allows fake apps to get admin privileges on the infected device. Hydra can abuse this permission to lock the device, modify or reset the screen lock PIN, etc.” 

Other rights are requested by the malware to carry out harmful activities such as accessing SMS content, sending SMSs, making calls, modifying device settings, spying on user activity, and sending bulk SMSs to the victim's contacts: 
  • CHANGE_WIFI_STATE : Modify Device’s Wi-Fi settings 
  • READ_CONTACTS: Access to phone contacts 
  • READ_EXTERNAL_STORAGE: Access device external storage 
  • WRITE_EXTERNAL_STORAGE: Modify device external storage 
  • READ_PHONE_STATE: Access phone state and information 
  • CALL_PHONE: Perform call without user intervention 
  • READ_SMS : Access user’s SMSs stored in the device 
  • REQUEST_INSTALL_PACKAGES : Install applications without user interaction 
  • SEND_SMS: This allows the app to send SMS messages 
  • SYSTEM_ALERT_WINDOW: The display of system alerts over other apps 
The code analysis shows that many classes are missing from the APK file. To avoid signature-based detection, the malicious code uses a custom packer. 

Cyble concluded, “We have also observed that the malware authors of Hydra are incorporating new technology to steal information and money from its victims. Alongside these features, the recent trojans have incorporated sophisticated features. We observed the new variants have TeamViewer or VNC functionality and TOR for communication, which shows that TAs are enhancing their TTPs.” 

“Based on this pattern that we have observed, malware authors are constantly adding new features to the banking trojans to evade detection by security software and to entice cybercriminals to buy the malware. To protect themselves from these threats, users should only install applications from the official Google Play Store.” 

18 million potential targets

Commerzbank has 13 million German clients and another 5 million in Central and Eastern Europe. This amounts to a total of 18 million potential targets, which is always an important factor for malware distributors. 

Typically, threat actors utilise SMS, social media, and forum postings to direct potential victims to malicious landing pages that install the APK on German devices. 

If anyone believes they have already fallen into Hydra's trap, it is suggested that they clean their device with a trustworthy vendor's security tool and then do a factory reset.