As described in the previous article, a Malware campaign has been identified that uses GoogleAds to advertise the download of a fake Notepad++ installation. By analyzing the code it was possible to identify the presence of the RedLine Stealer.

By downloading from the fake website, you obtain the ZIP file (

Evidenza del file di installazione Notepad++
SHA-256: 9F7B0E7B7254DF1F1F723F5F048C7D5A864CBED4BB875732BEFD33ECDA645E54

1- Installation File

file di installazione
SHA-256: D7CD49477AD1B8C676DC3507372CA774A69AF98280DB45A1C9AD0C5F0A4C309E

2- Compromise Launch

Starting the installation file launches the process of compromising the system alongside the actual installation of the Notepad++ software. The DRIVER~1.exe file, written using the .NET framework, is written to disk.

MD5:     215f71b938daacad9625b251c880264a
SHA-1:   22689156e4318332f2560f1a4909febc19226582
SHA-256: f2394824fcf883e783347ca22f5c610c65e6168e428d382e89fff96b70ae7dc2

The presence of numerous goto instructions, conveyed by controls and operations on the num variable and the use of names for variables, functions and classes not related to the semantics of the program gave evidence of the application of code obfuscation and virtualization procedures.

3- Analisi Dinamica

By performing dynamic analysis activities, it was possible to identify the first instruction of the Redline Malware:


which in turn calls the IsEnumSourceLength method from the same class

Loading the dll contained in the executable
Decoding the dll contained in the executable

The function performs decoding and loads an array of bytes into memory. These are extracted and saved in a file (Sbpxsycujbk.dll):

Sbpxsycujbk.dll 6903D034420A0FA693EFF7E32B8837567C4E7E2E60FD4197C663CCDA3331FD38
SHA-256: 6903D034420A0FA693EFF7E32B8837567C4E7E2E60FD4197C663CCDA3331FD38

The program continues by constructing the name of a method of the newly imported dll which will subsequently be invoked. The method involved is Xxgynyqprkwmjd.Wulxsfeuvyfwxzwxcdyric().

Construction of the name of the method to be invoked
Construction of the name of the method to be invoked

The dll makes use of the .NET framework, whose features relating to code obfuscation and virtualization are similar to those of the main executable. Specifically, it is Eazfuscator.NET which allows different levels of obfuscation and virtualization of .NET code.

The dll was imported into a C# program that invokes its method. In this way, the use of the RedLine Malware configuration extracted from a sequence of bytes and subsequently transformed into a C# object was identified:

Malware Configuration
Using malware configuration

4- Malware behavior and configuration

The behavior of Malware (RedLine) can be summarized in a series of steps:

  • 10 seconds wait to slow down execution: a process is launched with the command “cmd /c timeout 10”
Process Execution
Execution Details
  • Enumeration of process modules: the modules loaded by the process are enumerated and the presence of SbieDll.dll is checked among them
Enumeration of modules loaded by the process
  • AntiVM: WMI queries are performed to search for the presence of values attributable to virtualized systems
WMI query for recognizing virtualized systems – Pt.1
AntiVM based on keyword searches within system information – Pt.1
  • Further keyword research for recognizing virtualized systems
WMI query for recognizing virtualized systems- Pt.2
AntiVM based on keyword searches within system information – Pt.1
  • Writing to disk and running the actual Notepad++ software installer: The Notepad++ software installer is saved to a temporary folder and then executed
Construction of the installer path
Writing and execution of the installer
  • Decoding and injection of a further executable: an array of bytes is decoded and subsequently injected into the software process.
Checking the existence of InstallUtil before injection

5- RedLine Beacon

The executable injected into memory, which was extracted and analyzed, turns out to be a RedLine beacon whose configuration is encoded in a data structure and whose attribute content has been encrypted through the use of a secret key (also contained in the configuration).

Beacon Configuration

The values are deciphered by specific methods present in the executable. The decryption method identified appears to be related to a simple cipher based on the XOR operation

Method used for deciphering string

The RedLine beacon is made up of some features characteristic of a certain type of program, from code execution to the search for specific system components (processes, RAM, files, etc…). The activities to be carried out (tasks) are requested from the command and control server and executed by the program.

Some features of the beacon

5- External References – RedLine

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