Trojan-Dropper:W97M/Kukudro is a trojan-dropper embedded in the macro code of a Microsoft Word document.
Based on the settings of your F-Secure security product, it will either move the file to the quarantine where it cannot spread or cause harm, or remove it.
This malware was first spammed to various emails addresses, as zip archive file named my_Notebook.doc. Once a user opens the document, it drops and runs a binary executable. Later distributions runs may use varying names for the infected document.
The trojan-dropper is written in Visual Basic for Applications (VBA).
When the infected Word document is opened, the macro code inside of it will be executed. It will decode a binary file from its code and drop it as 666inse_1.exe to the root of the C: drive. The macro will then execute the dropped 666inse_1.exe file and end.
The binary executable is a trojan-downloader called Small.DCU.
In Office 2003 or later, the macro will only execute if macros have been enabled from Word's security settings.Otherwise, the trojan uses a vulnerability in MS Word 97, 2000 and XP; in this case, the macro will be able to execute even though macros are supposed to be disabled.
More information on this vulnerability is available at: https://www.microsoft.com/technet/security/Bulletin/MS01-034.mspx.
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