The Qua or Quaverse Remote Access Trojan (QRAT) is a Java-based RAT that can be used to gain complete control over a system. Introduced in 2015, QRAT was marketed as an undetectable Java RAT and is offered under the software-as-a-service model. Just after its original debut, we blogged about QRATs being spammed. As shown in Figure 1, the functionality of the spammed QRATs can be extended through the plugins offered by Quaverse.
Recently, we have encountered more spam campaigns that attempt to spread QRATs. The initial malware contains a subscription account for QHub (user:<digits>@qhub-subscription[.]store[.]qua[.]one), a service that offers a single interface to control remote machines. Its domain qua.one contains the same logo as to Quaverse’s website we have seen way back in 2015.
This spam campaign using QRAT malware has multi-stage downloaders. The first one is a JAR file that may arrive as an email attachment or can be downloaded from a link contained in a spam message. All the JAR files we have collected related to this campaign are obfuscated using the Allatori Obfuscator – the class names all have the same name and length but have different case.
The first downloader has 2 major functions. These are setting up the Node.Js platform onto the system, and then downloading and executing the second-stage downloader.
Firstly, upon the execution of the JAR file, the process architecture of the system will be checked, and that information will be used in downloading the appropriate Node.js for the machine. The JAR files we observed downloaded Node.Js version 13.13.0 from https://nodejs.org/dist/v13.13.0/node-v13.13.0-win-<x86|x64>.zip and extracted its content at %userprofile%/qnode-node-v13.13.0-win-<x86|x64>.zip. The JAR files were designed to run in Windows environments only.
Secondly, the JAR file Spec#0034.jar downloaded wizard.js from its command and control servers (C&Cs) then saved it under the qnodejs folder located inside the Node.js installation path. Then, the JAR file executed wizard.js with the C&Cs and the QHub service subscription user as arguments, as shown in Figure 6.
The downloaded file wizard.js is the second stage downloader written in Node.Js. This script file is responsible for setting the persistence of this threat, and the downloading and execution of the payload. Just like the JAR file, this supports the Windows platform only. Without the arguments from the JAR file, this script will not work.
We were able to obtain the file wizard.js, from hxxps://environment[.]theworkpc[.]com/scripts/wizard[.]js, through the JAR file from Figure 5. The file wizard.js is encrypted using Base64. Looking through its decrypted code, this script has its own defined modules.
The first main function of wizard.js is to set its persistence. The file qnode-<8 hex>.cmd will serve as the autorun file and written in it are the same arguments that the JAR file downloader set on wizard.js (see Figure 6) appended with a “--delegate” command.
Then, based on the platform and architecture of the system its running on, wizard.js will download the main malware. Using the C&Cs from the JAR file in Figure 4, we were able to download qnodejs-win32-ia32.js on 24-July-2020.
Before downloading, as shown in Figure 9, the script wizard.js verified the sha1 of the main malware qnodejs-win32-ia32.js through the file qnodejs-win32-ia32.sha256. Lastly, the main malware was executed using the same arguments supplied to wizard.js in Figure 6 plus a “serve” command after the path of qnodejs-win32-ia32.js.
Just like the downloader wizard.js, the main payload qnode-win32-ia32.js is written in Node.Js, its code is encrypted with Base64, and it has its own written modules. It contains an encrypted Node.Js packages folder node_modules hence its size is almost 12KB.
The Node.Js script uses the string “qnode-service” as the node command name and requires the arguments --central-base-url and --group when executed.
The QRAT qnode-win32-ia32.js has the following functionalities:
Some of the information, like the machine’s UUID, tags, and labels generated by the malware, will be written in the config file %userprofile%/<hex>-config.json. Meanwhile, the malware will use the service hxxps://wtfismyip[.]com to obtain network information.
This threat will communicate to its C&Cs through the Websocket connection protocol and below is the list of commands related to the 3 functions of the QRAT qnode-win32-ia32.js file mentioned above.
Remote access trojans are one of the commodity malware nowadays. With services like QHub, RATs can be a more attractive instrument to the threat actors as the machines infected by the RATs can be easily monitored in an already available environment they offer. The QRAT and its downloader are currently supporting the windows platform for now. Since they leveraged Node.Js which is a cross-platform, there is a possibility that this threat will be enhanced to support other platforms in the future.
In terms of mitigation, we recommend blocking inbound emails with Java files outright at the email gateway. We have also added protection for this threat to the Trustwave Secure Email Gateway for our customers.
Spec#0034.jar (12139 bytes) SHA1: 36DA7F23828283B6EA323A46806811F8312DD468
Legal_Proceeding_concerning_Overdue_invoices_pdf.jar (12,241 bytes) SHA1: 42d843c74e304d91297e21e748f4b528df422316
wizard.js (14433 bytes) SHA1: D6B1D3317C0D938C8AF21F1C22FD1B338A06B1C2
qnodejs-win32-ia32.js (11916833 bytes) SHA1: 31F541074C73D02218584DF6C8292B80E6C1FF7D
hxxps://legalproceedings[.]uc[.]r[.]appspot[.]com/Legal_Proceeding_concerning_Overdue_invoices_pdf[.]jar
hxxps://rtdqhub[.]home-webserver[.]de/
hxxps://rtdqhub[.]redirectme[.]net
hxxps://environment[.]theworkpc[.]com
hxxps://environment[.]spdns[.]org