A new Cyber cyberespionage group called REDBALDKNIGHT Spreading advance Daserf Backdoor against Japanese based government agencies such as biotechnology, electronics manufacturing, and industrial chemistry systems.
Unlike other backdoors, it has some stealthy techniques to evade detection and its use steganography, embedding codes are using to hide the malicious code with a spreading medium such as images.
Attackers using some social engineering techniques as well to reach out their malware and indicator are mainly translated into the Japanese Language.
According to Trend Micro Report,The decoy documents they use in their attack chain are written in fluent Japanese, and particularly, created via the Japanese word processor Ichitaro.
“Decoy Documents” are automatically generated and stored on a file system by the D3 System with the aim of enticing a malicious user.The decoy documents contain several different types of bogus credentials that when used, trigger an alert.
This Decoy document sending Across to victims using Spearphishing Emails such as “disaster prevention” Plans for the targeted organization.
How Does Daserf Backdoor Attack Chain Works
Traditional Spearphishing emails are using for the intial entry point of REDBALDKNIGHT’s attacks with attacked Decoy document that contains Trojan downloader that will help to retrieve the original Daserf backdoor.
Once Victims opened the file, it will communicate with attacked owned compromised site and that will have embedded Daserf backdoor file.
Daserf Backdoor connected to another compromised site to Download an Image that will be either the encrypted backdoor configurations or hacking tool.
Execution Flow of Daserf Backdoor
Later Daserf Backdoor connect to its C&C and await for commands form Attacker to initiate the further Malicious activities.
In this case Trojan downloader act as an initial level of Backdoor that is capable of open the shell and also XXMM, xxmm2_ steganography is used to hide malicious code within an image file.
EDBALDKNIGHT’s tool can create, embed, and hide executables or configuration files within the image file with its tag and encrypted strings via steganography. An encrypted string can be an executable file or a URL.
Daserf Backdoor regularly undergo technical improvements used to evade the traditional antivirus detection also it users the MPRESS packer that helps to protect against AV detection and reverse engineering phase.
Source : GBHackers