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Hackers Drain Wallets via Cracked macOS Apps using Scripts Accessed From DNS Records


Hackers have found another clever way to transfer information-stealing malware to macOS users, apparently through DNS records that could hide malicious scripts.

The attack is being targeted to macOS Ventura and later, depending on the vulnerable applications repackaged as PKG files that include a trojan. 

Attack details

The attack was discovered by researchers at Kaspersky, following which they analyzed the stages of the infection chain. 

While downloading an Application/folder, victims tend to follow installation instructions, unaware that they are actually executing the malware. Following this, they open the bogus Activator window that asks for the administrator password. 

The malware uses the 'AuthorizationExecuteWithPrivileges' method to execute a 'tool' executable (Mach-O) after acquiring permission. If Python 3 is not already installed on the system, it installs it and appears to be "app patching."

The malware then contacts its C2 server, at a site named ‘apple-health[.]org,’ in order to obtain a base64- encoded Python script that is designed to run arbitrary commands on the targeted device. 

Researchers discovered that the attacker employed a clever technique to reach the C2 server at the right URL: a third-level domain name consisting of a random string of five letters and words from two hardcoded lists.

This way, the hacker was able to conceal its activity in traffic and download the Python script payload disguised as TXT records from the DNS server, which seem like common requests. 

Three TXT entries, each a base64-encoded portion of an AES-encrypted message containing the Python script, were included in the DNS server's response.

This first Python script served as a downloader for a second Python script that captures and sends information about the compromised system, including the CPU type, installed apps, directory listings, operating system version, and external IP address.

Kaspersky notes that during their analysis, the C2 provided upgraded copies of the backdoor script, indicating continuing development, but didn't see command execution, thus this might not have been deployed yet.

Additionally, two functions in the downloaded script search the compromised system for Bitcoin Core and Exodus wallets; if they are detected, they replace the original wallets with backdoored versions obtained from 'apple-analyzer[.]com.'

The code in the compromised wallets transmits to the attacker's C2 server the seed phrase, password, name, and balance.

Users usually do not get suspicious when their wallet app suddenly asks them to re-enter their wallet details, making them vulnerable to getting their wallets emptied. 

As indicators of compromise, the cracked software used in this campaign is made public in the Kaspersky study. According to the researchers, these applications "are one of the easiest ways for malicious actors to get to users’ computers."

While using cracked programs to trick users into downloading malware is a popular attack vector, the campaign that Kaspersky examined demonstrates that threat actors are sufficiently crafty to devise novel ways of delivering the payload, such as concealing it in a DNS server's domain TXT record.  

PUMA Network: Unmasking a Cybercrime Empire

A massive cybercrime URL shortening service known as "Prolific Puma" has been uncovered by security researchers at Infoblox. The service has been used to deliver phishing attacks, scams, and malware for at least four years, and has registered thousands of domains in the U.S. top-level domain (usTLD) to facilitate its activities.

Prolific Puma works by shortening malicious URLs into shorter, more memorable links that are easier to click on. These shortened links are then distributed via email, social media, and other channels to unsuspecting victims. When a victim clicks on a shortened link, they are redirected to the malicious website.

Security researchers were able to track Prolific Puma's activity by analyzing DNS data. DNS is a system that translates domain names into IP addresses, which are the numerical addresses of websites and other devices on the internet. By analyzing DNS data, researchers were able to identify the thousands of domains that Prolific Puma was using to deliver its malicious links.

Prolific Puma's use of the usTLD is particularly noteworthy. The usTLD is one of the most trusted TLDs in the world, and many people do not suspect that a link with a usTLD domain could be malicious. This makes Prolific Puma's shortened links particularly effective at deceiving victims.

The discovery of Prolific Puma is a reminder of the importance of being vigilant when clicking on links, even if they come from seemingly trusted sources. It is also a reminder that cybercriminals are constantly developing new and sophisticated ways to attack their victims.

Here are some tips for staying safe from Prolific Puma and other malicious URL shortening services:

  • Be wary of clicking on links in emails, social media posts, and other messages from unknown senders.
  • If you are unsure whether a link is safe, hover over it with your mouse to see the full URL. If the URL looks suspicious, do not click on it.
  • Use a security solution that can detect and block malicious links.
  • Keep your web browser and operating system up to date with the latest security patches.

The security researchers who discovered Prolific Puma have contacted the United States Computer Emergency Readiness Team (US-CERT) and the Department of Homeland Security (DHS) about the service. Both agencies are working to take down Prolific Puma's infrastructure and prevent it from being used to launch further attacks.

Prolific Puma is not the first malicious URL-shortening service to be discovered. In recent years, there have been a number of other high-profile cases of cybercriminals using URL shortening services to deliver malware and phishing attacks.

The discovery of Prolific Puma is a reminder that URL shortening services can be abused for malicious purposes. Users should be cautious when clicking on shortened links, and should take steps to protect themselves from malware and phishing attacks.

Uncovering the Decoy Dog C2 Exploit: Infoblox's Finds Dangerous Threat

Decoy Dog

Finding recent reports on Domain Name System (DNS) attacks may prove difficult as a report by IDC in 2021 highlighted that 87% of organizations encountered a DNS attack in 2020. 

Despite this, DNS is not typically considered a prominent target in attacks, likely due to complex security terminologies such as DNS over TLS or HTTP. According to a report by CloudFlare, DNS queries in plaintext can be encrypted with TLS and HTTP to ensure secure and private browsing. 

In spite of this, Akamai's DNS threat report for Q3 highlighted a rise of 40% in DNS attacks during the corresponding quarter of the previous year. Furthermore, during Q3 of the previous year, 14% of all safeguarded devices communicated with a malicious designation at least once.

A new malware toolkit called Decoy Dog

The Infoblox Threat Intelligence Group, which examines billions of DNS records and millions of domain-related records daily, has identified a new malware toolkit called Decoy Dog that employs the Pupy remote access trojan. 

RenĂ©e Burton, Senior Director of Threat Intelligence at Infoblox, revealed that Pupy is an open-source tool that is complex to utilize and inadequately documented. Infoblox's findings indicate that the Decoy Dog toolkit is being employed in less than 3% of all networks, and the threat actor who controls it is linked to only 18 domains. 

Through a sequence of anomaly detectors, the team discovered Decoy Dog's activities and learned that it had been running a data exfiltration command and control system since early April 2022 for over a year, which no one else had detected.

Russian links

Infoblox's researchers discovered that the Decoy Dog C2 was primarily originating from hosts located in Russia, according to an analysis of external global DNS data. 

The concern with this malware is that no one knows precisely what it controls, even though its signature is known. 

Burton explained that command and control allow an attacker to take over systems and issue orders, such as extracting all of an individual's emails or shutting down a firewall. She also stated that Pupy, which is linked to Decoy Dog, has previously been associated with nation-state activities, despite not being easy for the average cybercriminal to access due to its complexity and lack of instructions on establishing the DNS nameserver required for C2 communications.

The RAT effect

Similar to legitimate remote access tools that allow technicians to showcase new systems or make repairs, RATs are straightforward to install and do not affect the computer's processing speed. These malicious tools can be delivered via email, video games, software, advertisements, and web pages. Pupy is a RAT that has particular C2 functionalities.

As per Burton,
  • RATs allow access to a system and some use C2 infrastructure for remote control.
  • Pupy is a challenging-to-detect, cross-platform, open-source C2 tool primarily coded in Python.
  • Decoy Dog is a rare type of Pupy deployment that can be identified through its DNS signature. According to Infoblox, only 18 domains match this signature out of 370 million.

Some common uses of RAT malware involve an attacker acquiring remote access to a laptop, then leasing it out to other threat actors who install more malware through its network access. This can result in a laptop becoming part of a botnet.

Toolkits that are small and unusual can pose hidden dangers

Hidden RATs, or malware of unknown origin that remains undetected, can pose significant risks. For example, in 2018, Israeli cyber-arms firm NSO Group developed a C2 spyware called Pegasus that could infiltrate and control various mobile devices, giving remote hackers access to a phone's cameras, location, microphone, and other sensors for surveillance purposes.

Amnesty International became involved when the Saudi government allegedly used Pegasus to spy on the family of Jamal Khashoggi, who had been murdered by government operatives.

Amnesty International's Security Lab recently uncovered another commercial spyware that went unnoticed for two years and utilized zero-day attacks against Google's Android operating systems. However, Infoblox had already blocked 89% of those domains before Amnesty's report, providing protection to its customers and verifying Amnesty's findings, according to Burton.