Suspected CoralRaider Continues To Expand Victimology Using Three Information Stealers

Cisco Talos has disclosed details on a campaign that has been ongoing since February 2024 to distribute three information-stealing malware, including Crypbot, LummaC2, and Rhadamanthys. Updated versions of each of the payloads are being deployed in attacks, each equipped with new obfuscation techniques to evade detection and exfiltrate data of interest from targeted systems. Based on the TTPs observed, the latest campaign has been attributed to an actor dubbed CoralRaider, a suspected Vietnamese-origin group that has been active since at least 2023. In the attacks observed since February 2024, the actor is using the above-mentioned info-stealers to target victims’ information including system and browser data, credentials, cryptocurrency wallets, and financial information. The campaign seems to be worldwide as victims range from several countries, including the U.S., Nigeria, Pakistan, Ecuador, Germany, Egypt, the U.K., Poland, the Philippines, Norway, Japan, Syria and Turkey.

Security Officer Comments:
Notable about this campaign is the use of a Content Delivery Network cache by CoralRaider to store malicious files on their network edge host. This method of storing and downloading payloads enables the actors to avoid request delays and deceive network defenders. According to researchers, the infection chain typically initiates with the actors tricking victims into opening a ZIP archive containing a malicious Windows Shortcut or .LNK file. In this case, the .LNK file contains an embedded PowerShell command running a malicious HTA file on the attacker-controlled CDN domains. Once executed, the HTA file will execute an embedded Javascript, which then decodes and runs a PowerShell decrypter script to decrypt the embedded PowerShell loader script and run it in the victim’s memory. According to Cisco Talos, “the PowerShell Loader executes multiple functions to evade the detections and bypass UAC, and finally, it downloads and runs one of the payloads, Cryptbot, LummaC2 or Rhadamanthys information stealer.”

Suggested Corrections:
While it’s unclear how exactly the malicious archive files are being distributed to victims, researchers suspect the use of phishing emails embedded with malicious URLs designed to download these files via the drive-by download technique.

General phishing mitigation:

Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from its 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.