In this blog post, we review one of the latest malware examples that has recently surfaced.

Clipper malware is a type of malware that specifically targets cryptocurrency wallets. It replaces wallet addresses with the attacker’s own address, effectively diverting funds to the attacker. The danger of Clipper malware lies in its ability to intercept and manipulate sensitive information, such as wallet addresses, through various hooking techniques.

In this blog we review Paradies Clipper malware, which is uncommon in the wild due to its developer’s low popularity, but still interesting from a cyber research perspective.

Threat Intel

Let’s start from the beginning, at the source of the malware: a sales thread in the nulled.to forum. There, anyone can access the Clipper panel site, register, and buy a subscription.

Figure 1: The Clipper panel site

Static Info

To determine the basics about this malware, we opened a sample in DiE, a malware analysis tool. From there, we could see that the sample was written in C/C++ and that it is a PE32 file.

Figure 2: Malware written in C/C++ as a PE32 file

Looking at the strings of the sample, we noticed that the developer hasn’t invested time in obfuscating the strings. This enabled us to find what could be the C2 (and the compilation path on the developer’s computer):

Figure 3: Possible C2 and compilation path

We could also understand a lot by looking at the imports, no dynamic API resolution necessary:

Figure 4: The imports

Analysis

Opening up the malware binary in IDA, a disassembler tool, we found a long main function. The function first checks for a mutex handle with the value: 7CmLQX. If it exists, the program will understand that it is already executed and will terminate itself.

Figure 5: Mutex handle function

Persistence

The program then retrieves the path to the user’s AppDataLocal folder and combines it with the persistence executable name: Update.exe.

From there, the program compares the persistence path to the current path of the executable (it retrieves the path using GetModuleFileNameA). If the executable is not running from the persistence path (C:UsersuserAppDataLocalUpdate.exe), it will skip the main functionality code and create persistence:

Figure 6: Creating persistence

Figure 6: Creating persistence

The program creates a registry key with the name Update under the path HKCUSOFTWAREMicrosoftWindowsCurrentVersionRun with the value pointing to the persistence path.

Figures 7 & 8: Creating a registry path

Figures 7 & 8: Creating a registry path

Next, the binary concatenates a CMD command and executes it. The command copies the executable to the desired persistence path, deletes the executable, and executes it again from the persistent path.

Figure 9: Linking and executing the executable

The final concatenated command is as follows:

This command uses the attrib command with several flags:

  • +r  – sets the file as read-only.
  • +h – sets the file as hidden.
  • +a – flags the file as available for archiving when using the BACKUP or XCOPY commands.

The command uses the icacls command with several flags:

  • /deny “everyone” – denies specified user access rights.
  • WD – write data/add file.
  • AD – append data/add subdirectory.
  • WEA – write extended attributes.
  • WA – write attributes.

Figures 10 & 11: Command features

Once the persistence is made and the binary restarts we can dive into the Clipper functionality.

Main Functionality

The program starts off by creating the Mutex that the program initially tried to retrieve. The program then sleeps for a minute.

Figure 12: The program creates the Mutex and then sleeps

Before the Clipper begins the clipping function it creates the first connection to the Paradies server.

The first POST request that the Clipper makes contains the following fields:

  • username – the computer username (by using the GetUserNameA).
  • ip – the computer IP.
  • country – the country associated with the computer IP.
  • city – the city associated with the computer IP.
  • date – the initial infection date (followed up with the format DD-MM-YYYY).
  • time – the initial infection time.
  • last date & last time – the last active ping received from the infected computer.
  • mwv – Clipper version.
  • assigned – the associated ID of the builder in the web panel.
  • worker – affiliate ID.

Figures 13 & 14: The first POST request

In order to find the IP and the associated country/city, the program sends out three GET requests:

  1. https://myexternalip.com/raw with the user agent: hitman
  2. https://ipapi.co/{IP}/country with the user agent: hitman69
  3. https://ipapi.co/{IP}/city with the user agent: hitman1337

The first request to myexternalip.com retrieves the IP of the computer. The second and third requests to ipapi.co retrieve the country/city of the given IP.

Figure 15: Requests to ipapi.co

The program then constantly sends out pings to the web panel, letting the attacker know that the program is still alive. The POST request simply contains the following fields:

  • lastdate
  • lasttime
  • IP

Figure 16: The second POST request

The program then uses the next API calls to operate the clipboarding functionality:

  • OpenClipboard
  • GetClipboardData
  • CloseClipboard
  • EmptyClipboard
  • SetClipboardData

Once the program retrieves the data from the clipboard (using GetClipboardData) it tries to compare the data to crypto wallet regex patterns and, if the regex matches, the program replaces the wallet in the clipboard with the attacker’s wallet (using SetClipboardData).

Figure 17: Replacing the clipboard wallet

After the clipboard is switched, the program sends a POST request to the Paradies server, informing the attacker that the clipboard was changed. This includes the replaced wallet and to which wallet it was replaced. This request includes the below fields:

  • ip
  • previous
  • replaced
  • mwv
  • date
  • time
  • Assigned

Figure 18: Request to Paradies server

Summary

Paradies Clipper is a simple C++ malware with a dedicated mission. It aims to stay alive on the victim’s computer and monitor the clipboard data, in order to carry out the simple task of making money at the expense of the victim.

For more information about how to prevent malware, check out this blog.

IOCs

Sha256:

Paradies Clipper – 4df448d36e3409ecd712702ef66dba779d81961ae364243ccc0e2e5a6cb39334

Crypto wallets:

  • Bitcoin – bc1qxudtrupckfmc204z70x8p9xu7409nsrgvekm0h
  • Bitcoin – 1C7HpJnRNaUNY8F7inQXyxmJ9aQsczZAML
  • Litecoin – ltc1q259z50fwemrpjvjmkn5rl2m4h8jckm32rlhvem
  • Etherium – 0x301e8c4Dffaeb682b67bdfB5d340F36EFE2Cf877
  • Dogecoin – DE4hgzmrtaXVhTWRuzLpnyhbgRGikjBVvg
  • Ripple – rfvgDUeRUaDfGwPxnSj9aed4nroJgQcyDQ
  • Dash – Xh1ff4HdtbUtC2DW8vk3Dhwa5VSJ2pxSMG
  • Neo – LQ4Gwqr38zBR5JdyoxcUDu38r63T5mUi4Y
  • Monero – 41oqjME2WP2C88P3BW4oEgUGjMaXQwGqgirYJWCDYwAQahMXWKYNLF4XVodVkNQnF

Yara rule