North Korean Kimsuky Hackers Use Russian Email Addresses for Credential Theft Attacks
Summary:
Researchers at the South Korean cybersecurity company Genians have uncovered a series of email phishing attacks originating from Russian sender addresses that they link to the North Korea-aligned APT, Kimsuky. According to Genians researchers, the phishing emails were delivered through email services in Japan and Korea up until early September. However according to Genians, in mid-September, the adversary shifted the base of their email attacks from Japan and Korea to disguising them as if they were ostensibly sent from Russia in an attempt to evade detection. This tactic shift is accomplished by abusing VK’s Mail.ru email service, which entails the misuse of 5 alias domains: mail.ru, internet.ru, bk.ru, inbox.ru, and list.ru. Genians observed Kimsuky actors leveraging these sender domains for phishing campaigns that purport to be from financial institutions and internet portals, including Naver. VK Mail is a Russian email client similar to Gmail and Naver is an online South Korean community services platform. The attack chain outlined by Genians begins with a phishing attack impersonating Naver Mybox, a South Korean cloud storage service in various forms since late April, employing Japanese, South Korean, and U.S. domains as sender addresses until switching to Russian domains in mid-September. After further analysis, Genians determined the Russian domains used were fabricated leveraging a compromised Evangelia University email server and a PHP-based mailer service called Star to falsely register them.
Security Officer Comments:
Genians has determined the main goal of these phishing attacks is likely to perform credential theft so that this APT can use the information to launch follow-up attacks like BEC and move laterally. Kimsuky’s utilization of legitimate email tools like PHPMailer and Star in the past is well-documented by a report from Proofpoint in 2021. Kimsuky has proven to be adept at employing techniques to appear as a trusted party by spoofing email senders, helping them evade detection. It is important for organizations to be vigilant of these low-risk campaigns that don’t deliver malware as the credentials stolen are likely to be used as an infiltration route to launch more destructive attacks.
Suggested Corrections:
IOCs are available here.
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.
Link(s):
https://thehackernews.com/2024/12/north-korean-kimsuky-hackers-use.html
https://www.genians.co.kr/blog/threat_intelligence/kimsuky-cases
Researchers at the South Korean cybersecurity company Genians have uncovered a series of email phishing attacks originating from Russian sender addresses that they link to the North Korea-aligned APT, Kimsuky. According to Genians researchers, the phishing emails were delivered through email services in Japan and Korea up until early September. However according to Genians, in mid-September, the adversary shifted the base of their email attacks from Japan and Korea to disguising them as if they were ostensibly sent from Russia in an attempt to evade detection. This tactic shift is accomplished by abusing VK’s Mail.ru email service, which entails the misuse of 5 alias domains: mail.ru, internet.ru, bk.ru, inbox.ru, and list.ru. Genians observed Kimsuky actors leveraging these sender domains for phishing campaigns that purport to be from financial institutions and internet portals, including Naver. VK Mail is a Russian email client similar to Gmail and Naver is an online South Korean community services platform. The attack chain outlined by Genians begins with a phishing attack impersonating Naver Mybox, a South Korean cloud storage service in various forms since late April, employing Japanese, South Korean, and U.S. domains as sender addresses until switching to Russian domains in mid-September. After further analysis, Genians determined the Russian domains used were fabricated leveraging a compromised Evangelia University email server and a PHP-based mailer service called Star to falsely register them.
Security Officer Comments:
Genians has determined the main goal of these phishing attacks is likely to perform credential theft so that this APT can use the information to launch follow-up attacks like BEC and move laterally. Kimsuky’s utilization of legitimate email tools like PHPMailer and Star in the past is well-documented by a report from Proofpoint in 2021. Kimsuky has proven to be adept at employing techniques to appear as a trusted party by spoofing email senders, helping them evade detection. It is important for organizations to be vigilant of these low-risk campaigns that don’t deliver malware as the credentials stolen are likely to be used as an infiltration route to launch more destructive attacks.
Suggested Corrections:
IOCs are available here.
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.
Link(s):
https://thehackernews.com/2024/12/north-korean-kimsuky-hackers-use.html
https://www.genians.co.kr/blog/threat_intelligence/kimsuky-cases