Detecting IcedID... Could It Be A Trickbot Copycat? | Splunk
By Splunk Threat Research Team
Published: 2021-11-04 · Archived: 2026-04-06 00:43:58 UTC
IcedID targets financial institutions across different countries including banks, payment card providers, and e-commerce sites. IcedID has also been observed deployed in conjunction with other malware payloads such as
Valak, Qakbot, Conti Ransomware. It is clear from studying past campaigns that the actors behind IcedID have
expanded beyond banking information in order to extend similar features and coverage as other popular carriers
such as Emotet or trickbot and by doing so current iterations of IcedID look more like a copycat or maybe even a
successor.
Spear Phishing Documents
In a recent campaign, malicious actors were observed using a document builder to simulate legitimate DocuSign
documents and embedding exploitation code for CVE-2017-8570 to trigger the installation of IcedID. These
documents were delivered via spear-phishing technique.
Below is the screenshot of the phishing campaign (Word and Excel) that will download the IcedID downloader as
soon as the user runs the malicious macro document in the targeted host.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 1 of 14

This malicious document will download the IcedID loader then drop it as a “.sys” or “.jpg” file and execute it
using regsvr32.exe windows application with “-s” parameter like the screenshot below.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 2 of 14

Other exploitation vectors include running an obfuscated HTML application (.hta) to download the DLL loader as
a .jpg file then execute it with rundll32.exe windows application with the “PluginInit” parameter. Below is the
screenshot of the macro code that executes the .hta file and the de-obfuscated .hta script shows how it downloads
and executes the first payload.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 3 of 14

IcedID Initial Downloader (Stage 1)
The initial IceID loader binary will decrypt another .dll file in memory to download the 2nd stage payload (png or
.dat) files. This is done by initially connecting to aws.amazon.com to check the internet connection and to prepare
its initial C2 communication.
IcedID Payload Loader - PhotoLoader and “License.dat” decrypter) (Stage 2)
Once the second stage payload is downloaded, It will load a shellcode or headless executable file which is the
main IcedID bot. This shellcode can be extracted either in .png file format (payload obfuscated by steganography)
or gzip payload format containing a “license.dat” file.
The next code snippet below shows the .dll in memory locating the .png payload in a randomly generated
directory based on the user name of the compromised machine created in either %appdata% or “C:\Programdata”.
If the .png file payload is found in either of those two folder paths, it will decrypt the shellcode from the image
file if not it tries to download from the C&C server.
For the gzip file, It uses a similar code to locate the “license.dat” payload, aside from having an additional
parameter check “/i” in the syntax line, as seen in the screenshot below.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 4 of 14

IcedID .PNG Steganography and “License.dat” Payload
The PNG payload uses steganography to hide the shellcode inside the PNG. The encrypted shellcode and the 8
bytes rc4 decryption keys are placed in the IDAT chunk type structure of the PNG header file. A python script was
developed (IceIdPNGShellcodeExtractor.py) to automatically extract the shellcode on the said payload.
For the “license.dat” IcedID payload, it will decrypt it using its customized decryption algorithm using its last 16
bytes as the decryption key. In this case, the IceIdDecrypt.py tool can be used to decrypt license.dat and do a static
analysis of the file.
IcedID Core/Main Bot (Stage 3)
The shellcode or the core IcedID BOT will be injected in either spawned svchost.exe system processor in
msiexec.exe or within the memory space of a rundll32 process that loads the .dll shellcode decryptor. After that, it
will hook some native API, create a mutex as a mark of its infection, and make sure only one instance is running.
Below are other notable behaviors seen in this main bot.
Hook Browser:
This shellcode will try to hook common browsers like firefox and chrome to steal credentials, cookies, and
sessions saved. The screenshot below shows what it looks like in firefox and chrome browsers in the compromised
machine.
Desktop Screenshots:
This code displays the ability to take screenshots of the desktop window of the compromised host. This bitmap
image file format will be saved in the temp folder with a .tmp file extension to blend on normal .tmp files
activities.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 5 of 14

Passff.tar and cookie.tar
It will also create files named “passff.tar” for the browser history and “cookie.tar” for the browser cookies that
may contain stolen browser information.
Stealing Browser Information
IcedID will also download and load a “sqlite64.dll” in the %temp% folder that will be needed for parsing firefox
and chrome browser database to extract information. Below are SQLite commands decrypted in the shellcode to
harvest autofill information from browser .db like cookies, password, company_name, street_address, city, state,
zip code, country_code, phone number, user full name, and credit card information.
UAC Bypass
The following are two functions to Bypass UAC (User Account Control). The Eventvwr and the fodhelper UAC
bypass technique.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 6 of 14

Harvest Email/Outlook Information and Browser Password Storage
Exfiltration tasks also include querying several registry keys related to email client Microsoft Outlook to steal user
profiles, email signatures, and stored password folders through registry and ActiveMail Partners. “%u” is the
outlook version installed in the machine.
Recon AV Product
The following PowerShell commands detect Antivirus Product information.
Other Execution and RemoteThread Execution
We also found chcp command execution and passage of the result to a created pipe. The result of this command
line may give the locale country region of the compromised host base on its result. For example, the 437 result
means “default code page in the US”.
Another regsvr32 execution with “/s” parameter to execute DLL payload downloaded from its C2 server, copy of
itself or decrypted DLL that was dropped in the compromised host.
Code injection into a cmd.exe process.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 7 of 14

Persistence
IcedID creates a scheduled task entry to download the file that will decrypt and load the license.dat file using a
process spawned via the Rundll32 application, as seen in the screenshot below.
In addition to using scheduled tasks for spawning processes, the main bot is also capable of creating a regrun entry
for its DLL payload using SHSetValueA API. This will ensure that the DLL will be loaded every time a user logs
on.
Create Self Signed Certificate
IcedID will also add certificates into the certificate store that will be saved in the %temp% folder as part of its
possible proxy communication to its C2 server bound to IP 127.0.0.1 port 54245. The screenshot below shows the
decrypted certificate format that IcedID will add to the certificate store in a .tmp file. This proxy function also
compliments the web inject vector as an alternative way to capture traffic and credentials.
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 8 of 14

The screenshot below shows how IcedID setup proxy from IP 127.0.0.1 port 54245 by listening on the created
socket relative to the IP and port mentioned above.
The following are several detection methods created by STRT to address IcedID. All these detections are
encompassed in an Analytic story released in our content updates.
Detections
Suspicious Rundll32 Plugininit (New)
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 9 of 14

Suspicious IcedID Rundll32 Cmdline (New)
Rundll32 Process Creating Exe Dll Files (New)
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 10 of 14

Suspicious IcedID Regsvr32 Cmdline (New)
Rundll32 CreateRemoteThread In-Browser (New)
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 11 of 14

Office Application Spawn Regsvr32 process (new)
Recon AVProduct Through Pwh or WMI (Modified)
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 12 of 14

CHCP Command Execution (New)
Create Remote Thread In Shell Application (New)
Drop IcedID License.dat (New)
IcedID Exfiltrated Archived File Creation (New)
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 13 of 14

SQLite Module In Temp Folder (New)
Contributors
We would like to thank the following for their contributions to this post: Teoderick Contreras and Rod Soto.
Source: https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
https://www.splunk.com/en_us/blog/security/detecting-icedid-could-it-be-a-trickbot-copycat.html
Page 14 of 14