BeaverTail and Tropidoor Malware Distributed via Recruitment Emails
Summary:
According to a new report from the AhnLab SEcurity intelligence Center (ASEC), threat actors were observed impersonating a recruitment email from a developer community called Dev.[]to to distribute malware. The attack involved a BitBucket link containing a project that, when accessed, revealed malicious files. These included BeaverTail, a malware disguised as "tailwind.config.js," and a downloader named "car.dll." BeaverTail, which is known to be used by North Korean hackers, is an infostealer and downloader that targets web browsers to steal sensitive data like login credentials and cryptocurrency wallet information. It is also capable of downloading additional payloads, including the InvisibleFerret malware. Whereas, the downloader, "car.dll," is designed to execute Windows commands internally, similar to the LightlessCan malware used by the notorious North Korean threat group, Lazarus.
In this case, researchers note the downloader executed commands that led to the deployment of a backdoor, "Tropidoor," which when decrypted connects to four C&C servers for further instructions. For its part, Tropidoor is designed to collect basic system information and generate an encryption key, which is transmitted to the C&C server using RSA encryption. Tropidoor is also capable of executing a variety of commands, such as capturing screenshots, deleting or modifying files, and running system commands like "schtasks," "ping," and "reg,” to maintain persistence and enable remote control over the compromised system.
Security Officer Comments:
The latest attack appears to be part of a larger trend in which BeaverTail is distributed through phishing campaigns, often disguised as legitimate job offers, similar to those targeting LinkedIn users. While BeaverTail samples have been discovered in South Korea, VirusTotal submissions indicate that these attacks have also targeted international victims, underscoring the malware's growing global reach. Given BeaverTail's association with North Korean threat actors, it is likely that the primary motivation behind these attacks is cyber espionage, coupled with the potential for generating funds to support the North Korean regime’s operations.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://asec.ahnlab.com/en/87299/
According to a new report from the AhnLab SEcurity intelligence Center (ASEC), threat actors were observed impersonating a recruitment email from a developer community called Dev.[]to to distribute malware. The attack involved a BitBucket link containing a project that, when accessed, revealed malicious files. These included BeaverTail, a malware disguised as "tailwind.config.js," and a downloader named "car.dll." BeaverTail, which is known to be used by North Korean hackers, is an infostealer and downloader that targets web browsers to steal sensitive data like login credentials and cryptocurrency wallet information. It is also capable of downloading additional payloads, including the InvisibleFerret malware. Whereas, the downloader, "car.dll," is designed to execute Windows commands internally, similar to the LightlessCan malware used by the notorious North Korean threat group, Lazarus.
In this case, researchers note the downloader executed commands that led to the deployment of a backdoor, "Tropidoor," which when decrypted connects to four C&C servers for further instructions. For its part, Tropidoor is designed to collect basic system information and generate an encryption key, which is transmitted to the C&C server using RSA encryption. Tropidoor is also capable of executing a variety of commands, such as capturing screenshots, deleting or modifying files, and running system commands like "schtasks," "ping," and "reg,” to maintain persistence and enable remote control over the compromised system.
Security Officer Comments:
The latest attack appears to be part of a larger trend in which BeaverTail is distributed through phishing campaigns, often disguised as legitimate job offers, similar to those targeting LinkedIn users. While BeaverTail samples have been discovered in South Korea, VirusTotal submissions indicate that these attacks have also targeted international victims, underscoring the malware's growing global reach. Given BeaverTail's association with North Korean threat actors, it is likely that the primary motivation behind these attacks is cyber espionage, coupled with the potential for generating funds to support the North Korean regime’s operations.
Suggested Corrections:
Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from their customers. If in doubt, users should verify with the company itself to avoid any potential issues.
Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.
As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.
Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.
Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.
Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.
Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.
Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.
Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.
Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.
It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.
If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.
Link(s):
https://asec.ahnlab.com/en/87299/