Insights and analysis by Miguel Ang
Figure 1. Sample email delivering Loki through LZH attachment
The LZH archive attachment contained the Loki dropper named bFbnF2vovw15SVM.exe. It also has a folder named “crypted_files,” which contains an empty folder named “myself_crypted” inside. This was either the result of an error in archiving the sample or was meant to be used to contain additional components or payloads.
Figure 2. Attachment contents
Figure 3. Contents of the “crypted files” folder
The Loki dropper uses .NET compiled binaries to add multiple layers of obfuscation. It eventually uses process hollowing to load and execute the main Loki payload. This method is reminiscent of the campaign that propagates Loki through CAB file attachments. The main Loki payload that it drops also has the same hash as the variant concealed through CAB files, indicating that both samples are under the same ongoing campaign.
Cybercriminals can use a variety of file attachments to spread malware, ranging from more common file types like Word Document or PDF, to less familiar ones like CAB or LZH files. Regardless of the file type used to conceal it, the fact remains that malware can compromise systems, disrupt device performance, or steal data. The following best practices can help prevent malware infections:
|File Name||SHA-256||Trend Micro
Like it? Add this infographic to your site:
1. Click on the box below. 2. Press Ctrl+A to select all. 3. Press Ctrl+C to copy. 4. Paste the code into your page (Ctrl+V).
Image will appear the same size as you see above.