On November 9, 2017, our Threat Guidance team received a request to analyze a malicious document intended to infect a targeted system with the Emotet
Emotet first emerged in 2014 as a Trojan designed to steal banking credentials and other sensitive
As the holiday season is upon us, extra care should be taken when interacting with emails that contain attachments purporting to be invoices or other business communications or links to
The sample analyzed in this report is a Microsoft Word Document that contains a malicious macro program which was developed to download the Emotet malware, which then searches the targeted system for sensitive information that will be exfiltrated to the command and control (C2) servers under the attackers’ control.
The attacker then can sell the information harvested, or login into the account themselves to steal more information. Emotet can spread itself to other systems by stealing an address book from one computer on the network.
Microsoft Word 97-2003 Document
As mentioned above, the first step of this attack arrives in the form of a malicious Microsoft Word file that contains a macro which requires the target to manually enable functionality (figure 1):
The script can have different obfuscator techniques, but at the
In this first macro, the obfuscator technique first replaces some characters of the code for other specific characters. Then the code was obfuscated and
In the second macro, the obfuscator technique first encodes all the code in decimal code, then split it with different characters and decodes the result with base64. This obfuscate code is saved
The original code of these two different macros is basically the same as you can see in Figures 5 and 6:
The script leverages PowerShell (Figure 7) to download and execute the Emotet malware payload as certproc.exe (Figures 8 and 9):
The certproc.exe file creates a copy in the folder \%AppData%\local\microsoft\windows\certproc.exe that is then persistent in the registry, as you can see here in Figure 10:
The Emotet malware proceeds to search the infected system for sensitive information (Figure 11):
Once it has located information of interest to the attacker, it proceeds to exfiltrate the data to a C2 server with the IP address 220.127.116.11 (Figure 12):
To avoid being the victim of the Emotet campaign, organizations should ensure that basic security best practices are being adhered to, particularly around the handling of email with attachments and/or URL links.
Indicators of Compromise (IOCs)
- 18.104.22.168 oilcom[.]com[.]ua
- 22.214.171.124 www[.]avcilarbinicilik[.]xyz
- 126.96.36.199 randevu-dk[.]ru
- 188.8.131.52 taswines[.]co[.]uk