Magniber Ransomware Attempts to Bypass MOTW (Mark of the Web)

The ASEC analysis team uploaded a post on October 25th to inform the users of the changes that have been made to the Magniber ransomware. Magniber, which is still actively being distributed, has undergone many changes to evade the detection of anti-malware software. Out of these changes, this blog will cover the script format found from September 8th to September 29th, 2022, which bypassed Mark of the Web (MOTW), a feature offered by Microsoft that identifies the source of files….

Emotet Being Distributed Again via Excel Files After 6 Months

Over multiple blog posts, the ASEC analysis team has released information on the distribution of Emotet which had been modified in many different ways. It has recently been identified that the Emotet malware has become active again. Around six months have elapsed since the last active distribution. This post will examine the differences between the current Excel file and the one that had been distributed in the past. The common characteristics include the fact that it is distributed through an…

HackHound IRC Bot Being Distributed via Webhards

Webhards are the main platforms that the attackers targeting Korean users exploit to distribute malware. The ASEC analysis team has been monitoring malware types distributed through webhards and uploaded multiple blog posts about them in the past. Generally, attackers distribute malware through illegal programs such as adult games and crack versions of games. Those who use webhards as a distribution path typically install RAT type malware such as njRAT, UdpRAT, and DDoS IRC Bot. As shown in the cases covered…

ASEC Weekly Malware Statistics (October 31st, 2022 – November 6th, 2022)

The ASEC analysis team is using the ASEC automatic analysis system RAPIT to categorize and respond to known malware. This post will list weekly statistics collected from October 31st, 2022 (Monday) to November 6th (Sunday). For the main category, downloader ranked top with 64.8%, followed by infostealer with 25.9%, backdoor with 6.6%, ransomware with 2.2%, and CoinMiner with 0.4%. Top 1 – BeamWinHTTP BeamWinHTTP is a downloader malware that ranked top with 39.6%. The malware is distributed via malware disguised…

Distribution of Word File (External + RTF) Modified to Avoid Detection

Malicious MS Office Word documents have long been used for the distribution of additional RTF malware by exploiting the fact that Word files allow external connection. However, AhnLab has identified the files that seem to have been made to avoid anti-malware detection are being distributed in Korea. Similar to past cases, an email disguised as a work email with a Word document attachment is used, but a unique factor exists in the webSettings.xml.rels file which can be identified within the…