Janeleiro, the time traveler: A new old banking trojan in Brazil
By Facundo MuñozMatías Porolli
Archived: 2026-04-29 07:40:03 UTC
UPDATE (April 6th, 2021):
Although we have not received any official response from GitHub, when we checked April 6th at around 18:00 UTC, the
malicious repositories used by Janeleiro had been taken down.
ESET Research has been tracking a newly discovered banking trojan that has been targeting corporate users in Brazil since
2019 across many verticals affecting sectors such as engineering, healthcare, retail, manufacturing, finance, transportation,
and government.
This new threat, which we've named Janeleiro, attempts to deceive its victims with pop-up windows designed to look like
the websites of some of the biggest banks in Brazil. These pop-ups contain fake forms, aiming to trick the malware’s victims
into entering their banking credentials and personal information that the malware captures and exfiltrates to its C&C servers.
Janeleiro follows exactly the same blueprint for the core implementation of this technique as some of the most prominent
malware families targeting the region: Casbaneiro, Grandoreiro, Mekotio, Amavaldo, and Vadokrist, among others.
In contrast to those well-known malware families, Janeleiro is written in Visual Basic .NET, a big deviation from the favored
Delphi programming language that threat actors in the region have been using for years. Janeleiro has been evolving towards
the objective of giving more control to the operators to manipulate and adjust its fake pop-up windows based on what they
need to pull off the attack, send mouse clicks and keystrokes, and recording user input and the screen in real time. The
nature of these types of attack is not characterized by their automation capabilities, but rather by the hands-on approach: in
many cases the operator must adjust the windows via commands in real time.
The operators seem comfortable using GitHub to store their modules, administering their organization page, and uploading
new repositories every day where they store the files with the lists of C&C servers that the trojans retrieve to connect to their
operators. Having your malware depend on a single source is an interesting move - but what if we told you that the newest
version of Janeleiro only lives for one day?
Target: Brazil
Based on our telemetry data, we can affirm that this malware targets only corporate users. Malicious emails are sent to
companies in Brazil and, even though we do not think these are targeted attacks, they seem to be sent in small batches.
According to our telemetry, the affected sectors are engineering, healthcare, retail, manufacturing, finance, transportation
and government.
An example of a phishing email is shown in Figure 1: a false notification regarding an unpaid invoice. It contains a link that
leads to a compromised server. The retrieved page simply redirects to the download of a ZIP archive hosted in Azure. Some
other emails sent by these attackers don’t have a redirection via a compromised server but lead directly to the ZIP archive.
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Figure 1. Example of a malicious email
The servers that host these ZIP archives with Janeleiro have URLs that follow the same convention as other URLs that we
saw delivering other banking trojan families (see the Indicators of Compromise section). In some cases, these URLs have
distributed both Janeleiro and other Delphi bankers at different times. This suggests that either the various criminal groups
share the same provider for sending spam emails and for hosting their malware, or that they are the same group. We have not
yet determined which hypothesis is correct.
An overview of the attack is shown in Figure 2.
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Figure 2. Janeleiro attack overview (simplified)
The ZIP archive contains an MSI installer that loads the main trojan DLL. Using an MSI installer is a favored technique of
several malware families in the region. Janeleiro retrieves the computer’s public IP address and uses a web service to
attempt to geolocate it. If the returned country code value does not match BR, the malware exits. If the geolocation check
passes, Janeleiro gathers information of the compromised machine, including:
Current date and time
Machine name and username
OS full name and architecture
Malware version
Region name obtained when geolocating the computer
The information is uploaded to a website with the purpose of tracking successful attacks. After that, Janeleiro retrieves the IP
addresses of the C&C servers from a GitHub organization page apparently created by the criminals. Then it is ready to start
its core functionality and wait for commands from an operator.
In 2020 ESET published a white paper detailing findings about interconnectivity of the most prominent Latin American
families of banking trojans including Casbaneiro, Grandoreiro, Amavaldo among others.  The similarities described in that
paper are in the implementation of the trojan’s core: notifying the operator when there is an active window with an
interesting name or title based on a predefined keyword list, and using a fake pop-up window to trick potential victims into
thinking they are entering sensitive information on a legitimate website. This process is illustrated by the flowchart in Figure
3.
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Figure 3. Typical core implementation of banking trojans from Latin America
Janeleiro follows the exact blueprint for its core implementation as eleven other malware families that target Brazil. As
shown in Figure 4, we can see some of the fake pop-up windows created by Janeleiro.
Figure 4. Fake pop-up windows used by Janeleiro
Janeleiro in action
Janeleiro begins enumerating windows and checking their titles to find interesting keywords (as shown in Figure 5) that
would indicate that the user is visiting the website of a banking entity of interest, especially those that are supported by its
implementation of fake pop-up windows.
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Figure 5. List of keywords that Janeleiro searches for in window titles
When one of the keywords is found, Janeleiro immediately attempts to retrieve the addresses of its C&C servers from
GitHub and connects to them. These fake pop-up windows are dynamically created on demand and controlled by the
attacker via commands to the malware, as they go through several stages to trick the user while the attacker, in real time,
receives screen captures, the logged keystrokes and information that is entered in the fake forms.
The fact that threat actors abuse GitHub is nothing new; however, Janeleiro does it in quite interesting ways: the operators
have created a GitHub organization page that they rename every day in the form SLK<dd/mm/yyyy> where <dd/mm/yyyy>
is the current date.
A screenshot of the GitHub organization page as it looked on 15 March 2021 is shown in Figure 6.
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Figure 6. GitHub organization page with repositories used by the operators of Janeleiro
Daily, the operator novoescritorio1-alberto creates a new repository following this naming format. The purpose of the
repository is to contain a file that has the list of IP addresses for Janeleiro’s C&C servers where it connects to report to its
operators, to receive commands and to exfiltrate information in real time.
A screenshot showing one of the repositories in the GitHub organization page attributed to Janeleiro’s operators is shown in
Figure 7, including the username of the account that does the commits.
Figure 7. Main branch with the SLK file for Janeleiro version 3
A screenshot of the secondary branch in the repository is shown in Figure 8.
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Figure 8. SLK branch with the SLK file for Janeleiro version 2
We have notified GitHub of this activity but at the time of writing no actions have been taken against the organization page
nor the account that creates the repository with new C&C server addresses.
In the newest version of Janeleiro, version 0.0.3, the developers introduced an interesting encryption/decryption feature
using an open-source library called EncryptDecryptUtils. The new procedure for decryption is shown in Figure 9.
Figure 9. Procedure for decryption implemented by Janeleiro version 0.0.3
To decrypt a string, Janeleiro encrypts the string resulting from the current date and the result is then used as a passphrase
and salt value to create a new key for decryption. This has an extremely important effect: the newest version of Janeleiro
can only decrypt its strings on one intended day. That could be the same day the strings were encrypted or one day in the
future; on any other day, the decryption fails.
This is also true for the contents of the SLK file in the main branch: the encrypted and base 64 encoded list of C&C servers
as shown in shown in Figure 10.
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Figure 10. Contents of the SLK file in the main branch.
The contents are encrypted with the same procedure: when Janeleiro decrypts the contents of the file it must be on one
specific date – the current date – to work as intended.
Evolution of Janeleiro
Janeleiro has an internal version value (as shown in Figure 11) that can be used by the attackers to identify which version of
their malware successfully compromised a machine. As of March 2021, we have identified four versions, but with two of
them sharing the same internal version number.
Figure 11. Configuration values used by version 0.0.2A from 2020
While in 2021 we have seen versions 0.0.2 and 0.0.3, we were interested in finding a missing key piece in the evolution of
Janeleiro: version 0.0.1, which should have been in existence in late 2019 or early 2020. To our surprise we found version
0.0.4 samples instead dating to 2019. These new samples of the trojan were deployed by a DLL loader component in tandem
with a password stealer, which means the group behind Janeleiro has other tools in their arsenal.
An overview of Janeleiro’s versions from 2019 through 2021 is shown in Figure 12.
Figure 12. Janeleiro’s strange evolution timeline, based in the internal version of the malware
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The inconsistency in the timeline and internal versioning of the malware suggests that it was under development as far back
as 2018, and in 2020 they decided to switch to a previous version of their code and to improve that and refine its command
processing for the operator to have better control of the trojan during the attack.
Breaker and keeper of traditions
While Janeleiro follows the same blueprint for the core implementation of its fake pop-up windows, along with other
malware families that ESET has documented in the region, it sets itself apart from those malware families in several ways:
It is written in Visual Basic .NET: The curious case of Brazil is that it is mostly targeted by banking trojans
developed in Delphi – the programming language of choice for several threat actors that are apparently working
together sharing tools and infrastructure. Janeleiro’s preference for VB.NET is a notable deviation from what appears
to be the norm for the region.
No binary obfuscation: While Janeleiro does make use of light obfuscation by generating random names for its
classes, modules, method names, parameters, and string encryption, it does not employ packers to make detection and
analysis harder. Other trojans such as Grandoreiro, Mekotio, Ousaban, Vadokrist and Guildma make heavy use of
Themida and binary padding techniques.
No custom encryption algorithms: Janeleiro’s developers rely on cryptographic functions provided by the .NET
Framework as well as open-source projects for string encryption/decryption, with a preference for AES and RSA
algorithms. Trojans such as Casbaneiro, Grandoreiro, Amavaldo, Mispadu, and Guildma, among others, use custom
encryption algorithms, including obfuscation techniques using string tables.
Simple method of execution: The MSI installer does not deploy other components besides the main trojan DLL or
execute further instructions other than load and execute one of the exports of the DLL that installs itself in the
system. We have found no samples of an MSI installer executing obfuscated scripts, unpacking support tools, or
components for DLL side-loading, which is popular with other malware families in the region.
No defense against security software: Some of the biggest banks in Brazil require a security module to be installed
by their customers before allowing them access to their bank accounts online; for example, Warsaw anti-fraud
software. It’s often the case that LATAM banking trojans try to find out if such software is installed in the
compromised machine and report it to the attackers. Some malware families such as Grandoreiro and Guildma
attempt to disable it in Windows Firewall or disable its driver.
Uses code from NjRAT: Janeleiro is far from being another incarnation of the well-known NjRAT, but it does use
NjRAT’s SocketClient and Remote Desktop capture functions, as well as other miscellaneous functions. NjRAT is
not commonly used – at least by LATAM baking trojans – perhaps because of their preference to use custom-made
trojans in Delphi. However, among other malware, NjRAT has been used in Operation Spalax, a campaign that
targets Colombia specifically.
Commands
Commands with parameters are received from the C&C server in encrypted form with the same algorithm used to encrypt
strings (see section Appendix A). A typical command format is like this:
%CommandName%%PredefinedSeparatorKeyword%%Parameters%.
After decryption the command is split into an array of strings; each part of the command is separated by a predefined
keyword hardcoded in the malware’s configuration – all versions we analyzed use |'meio'|, which separates the command
name and each parameter.
Figure 13 shows how Janeleiro checks the name of the command and executes the requested action.
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Figure 13. Example of Version 0.0.2B processing command startinfo
When Janeleiro sends data back to the operator, it does it in a similar format:
%CommandName%%PredefinedSeparatorKeyword%%Encoded data%.
The majority of Janeleiro’s commands are for controlling windows, the mouse and keyboard, and its fake pop-up windows.
As the development evolved from Version 0.0.2A to 0.0.3, more commands were added that offered the operator a more
refined control:
Commands to control specific window
Enumerate and send information about windows (title, class, handle)
Adjust specific window size, minimize, maximize
Dimensions of the screen
Kill all chrome.exe processes, and restart chrome.exe with arguments --disable-gpu
Capture the screen in real time
Keylogging in real time
Send keys and mouse clicks
Display or close a specific fake pop-up window
Show or close a specific fake pop-up window
Miscellaneous commands such as: send date and time, disconnect socket, terminate own process
Conclusion
The experimental nature of Janeleiro, going back and forth between different versions, tell us about an actor who is still
trying to find the right way to do it but is no less experienced than the competition: Janeleiro follows the unique blueprint for
the core implementation of the fake pop-up windows as many LATAM banking trojans, this does not seem to be a
coincidence or inspiration: this actor employs and distributes Janeleiro sharing the same infrastructure as some of the most
prominent of these active malware families. As we continue to track the activities of this actor, time will tell what new
developments they will come up with in the future.
For any inquiries, or to make sample submissions related to the subject, contact us at threatintel@eset.com.
Special thanks to Johnatan Camargo Zacarias from Itaú bank for his help with the investigation.
Indicators of Compromise (IoCs)
A comprehensive list of Indicators of Compromise (IoCs) and samples can be found in our GitHub repository.
SHA-1 hashes
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Version 0.0.4
SHA-1 Description ESET detection name
CF117E5CA26594F497E0F15106518FEE52B88D8D MSI file MSIL/TrojanDownloader.Agent.FSC
D16AC192499192F06A3903192A4AA57A28CCCA5A Console.exe loader MSIL/TrojanDownloader.Agent.FSC
462D6AD77860D3D523D2CAFBC227F012952E513C #rowspan# MSIL/Kryptik.TBD
0A5BBEC328FDD4E8B2379AF770DF8B180411B05D LoadDllMSI.dll loader MSIL/TrojanDownloader.Agent.FSC
0AA349050B7EF173BFA34B92687554E81EEB28FF System.Logins.Initial.dll MSIL/Agent.TIX
5B19E2D1950ADD701864D5F0F18A1111AAABEA28 #rowspan# #rowspan#
186E590239083A5B54971CAB66A58301230164C2 System.Modules.Initial.dll #rowspan#
E1B2FD94F16237379E4CAD6832A6FCE7F543DC40 System.Modules.Initial.dll MSIL/Janeleiro.A
4061B2FBEB7F1026E54EE928867169D1B001B7A5 #rowspan# #rowspan#
Version 0.0.2A
SHA-1 Description ESET detection name
8674E61B421A905DA8B866A194680D08D27D77AE Main Trojan Loader MSIL/Agent.AAI
2E5F7D5F680152E738B8910E694651D48126382A #rowspan# MSIL/Janeleiro.A
06E4F11A2A6EF8284C6AAC5A924D186410257650 Main Trojan MSIL/Agent.AAI
Version 0.0.2B
SHA-1 Description ESET detection name
291A5F0DF18CC68FA0DA1B7F401EAD17C9FBDD7F MSI file MSIL/Janeleiro.A
FB246A5A1105B83DFA8032394759DBC23AB81529 #rowspan# #rowspan#
6F6FF405F6DA50B517E82FF9D1A546D8F13EC3F7 Main trojan #rowspan#
742E0AEDC8970D47F16F5549A6B61D839485DE3C #rowspan# #rowspan#
Version 0.0.3
SHA-1 Description ESET detection name
455FAF2A741C28BA1EFCE8635AC0FCE935C080FF MSI file MSIL/Janeleiro.A
D71EB97FC1F5FE50D608518D2820CB96F2A3376F #rowspan# #rowspan#
158DA5AB85BFAC471DC2B2EE66FD99AEF7432DBB Main trojan #rowspan#
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SHA-1 Description ESET detection name
6BFAEFCC0930DA5A2BAEC19723C8C835A003D1EC #rowspan# #rowspan#
Download URLs
In the following <NNNNNNNNNNN> is a random number between 10000000000 and 90000000000.
Downloading only Janeleiro
https://recuperaglobaldanfeonline.eastus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNNN>
https://protocolo-faturamento-servico.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://acessoriapremierfantasiafaturas.eastus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
Downloading Janeleiro and other Delphi banking trojans
https://portalrotulosfechamento.eastus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://servicosemitidosglobalnfe.southcentralus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://emissaocomprovanteatrasado.eastus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
Downloading Delphi bankers
https://emitidasfaturasfevereiro.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://dinamicoscontratosvencidos.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://arquivosemitidoscomsucesso.eastus.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://fatura-digital-arquiv-lo.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://nota-eletronica-servicos.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
https://eletronicadanfe.brazilsouth.cloudapp.azure[.]com/nfedown.php?dw=<NNNNNNNNNN>
C&C servers
These are the IP addresses of the C&C servers where Janeleiro connects to report, receive commands and send data:
52.204.58[.]11
35.174.60[.]172
These are the tracking URLs where Janeleiro sends information about the compromised system during installation:
http://tasoofile.us-east-1.elasticbeanstalk[.]com/count
http://slkvemnemim.us-east-1.elasticbeanstalk[.]com/count
http://checa-env.cf3tefmhmr.eu-north-1.elasticbeanstalk[.]com/cnt/
These are the URLs used by System.Logins.dll to exfiltrate the harvested data:
http://comunicador.duckdns[.]org/catalista/emails/checkuser.php
http://comunicador.duckdns[.]org/catalista/lixo/index.php
IPs associated with the domain:
178.79.178[.]203
138.197.101[.]4
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MITRE ATT&CK techniques
Note: This table was built using version 8 of the MITRE ATT&CK framework.
Tactic ID Name Description
Resource
Development
T1584.004
Compromise Infrastructure:
Server
In some cases, malicious emails sent to targets
contain links to a compromised server that
redirects to the download of Janeleiro.
Initial Access T1566.002 Phishing: Spearphishing Link
Attackers send malicious emails that have a
download link for Janeleiro malware.
Execution T1204.001 User Execution: Malicious Link
Phishing emails sent by the attackers contain a
link to download a ZIP archive that holds an
MSI installer with Janeleiro malware.
Persistence
T1547.001
Boot or Logon Autostart
Execution: Registry Run Keys /
Startup Folder
Janeleiro achieves persistence by adding itself to
the Run registry key (in v0.0.3 of the malware).
T1547.009
Boot or Logon Autostart
Execution: Shortcut Modification
Janeleiro creates a LNK file for persistence (in
v0.0.4, v0.0.2A and v0.0.2B of the malware).
Defense
Evasion
T1140
Deobfuscate/Decode Files or
Information
Janeleiro v0.0.2B is obfuscated and its strings
are RSA-encrypted. Version 0.0.3 uses AES for
string encryption.
Credential
Access
T1555.003
Credentials from Password
Stores: Credentials from Web
Browsers
Janeleiro v0.0.4 can download a DLL that steals
passwords from Chrome, Firefox and Opera
browsers.
T1552.001
Unsecured Credentials:
Credentials In Files
Janeleiro v0.0.4 can download a DLL that
obtains passwords stored in files from several
applications such as FileZilla, Pidgin and
Thunderbird.
Discovery
T1087.003
Account Discovery: Email
Account
Janeleiro v0.0.4 can download a DLL that
collects Gmail addresses.
T1010 Application Window Discovery
Janeleiro collects information about open
windows so the attacker can decide to inject
pop-ups.
T1082 System Information Discovery
Janeleiro collects information from the victim’s
machine, such as username, OS and architecture.
T1033 System Owner/User Discovery
Janeleiro collects the username from the victim’s
machine.
T1124 System Time Discovery
Janeleiro collects current date and time when the
victim is compromised.
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Tactic ID Name Description
Collection
T1115 Clipboard Data
Janeleiro uses a clipboard event handler to
access clipboard data.
T1056.001 Input Capture: Keylogging Janeleiro can perform keylogging.
T1113 Screen Capture
Janeleiro can capture screenshots of the victim’s
desktop.
T1056.002
Input Capture: GUI Input
Capture
Janeleiro displays fake forms on top of banking
sites to intercept credentials from victims.
Command and
Control
T1095 Non-Application Layer Protocol Janeleiro uses TCP for C&C communications.
T1102.001
Web Service: Dead Drop
Resolver
Janeleiro uses GitHub repositories to store C&C
information.
Exfiltration T1041 Exfiltration Over C2 Channel
Janeleiro exfiltrates data over the same channel
used for C&C.
Appendix A: Overview of Janeleiro’s malware family
Here is each incarnation we have found of Janeleiro from 2019 until March 2021.
Version 0.0.4
Period of activity: 2019 – Possibly still active.
The first version of Janeleiro - that we know of - came in the form of an MSI installer and at least two variants:
Variant 1: MSI installer loads a DLL called LoadDllMSI.dll internally
Variant 2: MSI installer executes Console.exe, which checks privileges and loads an embedded DLL assembly
called LoadSystem.dll.
Both LoadDllMSI.dll and LoadSystem.dll perform the same tasks:
Create an installation folder
Download and store two modules: Logins.Initial.dll and System.Modules.Initial.dll. The two modules are
downloaded from a GitHub account that, at the time of writing, has been closed.
Create several Shortcuts in strategic places
Log the successful compromise of the system to a tracking website
System.Logins: It is a password stealer for Google Chrome, FileZilla, Mozilla Firefox, Opera, Pidgin, and Mozilla
Thunderbird. Additionally, it harvests email information from Gmail. All the information is exfiltrated to two websites.
Version 0.0.4 is the only one that is deployed with this malicious tool.
System.Modules: Janeleiro’s main trojan, implemented as a Windows Forms application compiled as DLL. This version
had the capacity to dynamically create fake pop-up windows using several Forms for several banking entities, including
banks operating in Mexico, but it is unknown if this version was distributed in Mexico at any point.
This version used two GitHub organization pages to download the IP addresses of its C&C servers: the names of the pages
are generated by encrypting the current date with SLK as suffix as shown in Figure 14.
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Figure 14. Version 0.0.4 attempts to read file in a GitHub repository that contains the encrypted list of C&C servers
At the time of writing, we believe that the operators have abandoned this version of the malware. We couldn’t find any
active GitHub pages by following the name generation algorithm used by Janeleiro.
Many commands for the trojan were left unimplemented, some were implemented and other discarded in newer versions
used in 2020 and 2021.
Version 0.0.2A
Period of activity: 2020 – Unknown.
Internal Malware Version: 0.0.2
The MSI installer loads a DLL that borrows from LoadSystem installation and persistence procedures but unpacks the
embedded main trojan DLL from its resources. The main trojan was implemented as a Windows Forms application compiled
as DLL.
This version of Janeleiro only uses one Form to create the fake pop-up windows with more commands supported by the
operator but with fewer targets: Mexican banking entities were discarded. All of the images used to cover the screen and
trick the user are for Brazilian banks.
This version also appears to have been abandoned and cannot contact its C&C servers by retrieving the IP lists from a
GitHub page. It uses the same algorithm as Version 0.0.4 with the same key vhpjzqqtpo, suggesting that the operators where
using the same GitHub page as for Version 0.0.4. Figure 15 shows the code that attempts to retrieve the list from GitHub.
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Figure 15. Version 0.0.2A attempts to download a new list of C&C servers from a repository on a GitHub organization page
Version 0.0.2B
Period of activity: 2021 – Still active.
Internal Malware Version: 0.0.2
New characteristics of this version:
Implemented as a Windows Presentation Foundation application
Major restructuration of the code combining the loader code with the main trojan
Geolocation of the compromised machine
Implementation of clipboard hijacking to replace bitcoin addresses
Expanded set of supported commands
Strings encrypted/decrypted with the RSA algorithm
Figure 16 shows the implementation of clipboard hijacking by Janeleiro; when a bitcoin address is found, it randomly picks
one from its own list of bitcoin addresses and replaces it.
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Figure 16. Janeleiro's implementation of clipboard hijacking
In this version a simplified procedure was implemented to retrieve the addresses of its C&C servers from a GitHub
organization page; the name scheme this time is a simple concatenation of SLK with the current date time without the
slashes, as shown in Figure 17.
Figure 17. Version 0.0.2B procedure to retrieve its list of C&C servers. We have decrypted some strings for clarity.
The code attempts to download the contents of a file in a secondary branch. The file contains, in plaintext, the list of the
C&C IP addresses and ports. At the time of writing, the GitHub organization pages can be found using the procedure as they
continue to operate with this recent version of Janeleiro.
Version 0.0.3
Period of activity: Since March 2021 – Still active.
Internal Malware Version: 0.0.3
New characteristics of this version:
Implemented as a Windows Forms application
A recombination of Version 0.0.2A and 0.0.2B code and technique implementations
New persistence method using Windows Registry Run Key
Expanded set of supported commands
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Uses AES algorithm to encrypt/decrypt its strings
This version uses the same procedure as Version 0.0.2B to get the C&C servers from the GitHub organization page, with the
difference that it uses the main branch within the repository and the list is encrypted and encoded with base64 as shown in
Figure 18.
Figure 18. Main repository containing an encrypted list of C&C servers
This procedure is also used when decrypting the list of C&C servers, therefore there must exist a repository containing the
file in the main branch, with the encrypted list intended for that day. Otherwise this version cannot contact the operators as
decryption will fail.
Appendix B: Third-party tools used by Janeleiro
Janeleiro uses several third-party, open-source libraries for various purposes:
Tool Description Used by
Fody
Used to load every other third-party tool, or trojan component, such
as LoadSystem in version 0.0.4.
All versions
including
System.Logins
Mimekit, Mailkit, Xnet,
BouncyCastle, uPREC
Used to collect emails and login information. System.Logins
SharpClipboard
Used for clipboard hijacking: when the user copies a bitcoin
address, Janeleiro replaces it with one randomly chosen from a list
of its own.
Interestingly, the Janeleiro developers don’t seem to have
downloaded SharpClipboard’s source code to compile their own
version: they obtained a compiled copy from another GitHub
repository; we don’t believe that user is in any way related to the
development of this threat.
Version 0.0.2B
Version 0.0.3
SharpVectors
Used to load SVG images contained in resources. These images are
logos of several banks used by the fake pop-up windows.
Version 0.0.2B
Version 0.0.3
Newtonsoft JSON Used to parse the data returned by the geoPlugin web service.
Version 0.0.2B
Version 0.0.3
EncryptDecryptUtils
Used to encrypt and decrypt its strings. Functions were modified to
contain the key, so it’s not present in the trojan’s code.
Version 0.0.3
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Source: https://www.welivesecurity.com/2021/04/06/janeleiro-time-traveler-new-old-banking-trojan-brazil/
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