In mid-March 2021, we find two new spam campaigns. The messages in both cases were written in English and contained ZIP attachments or links to ZIP files. Further research is demonstrated that both campaigns ultimately aimed to distribute banking Trojans. The payload in most cases was IcedID( Trojan-Banker.Win3 2. IcedID ), but we have also discover a few cases QBot( Backdoor.Win3 2. Qbot, also known as QakBot) samples. During campaign spikes we observed increased activity of these Trojans: more than a hundred detectings a day.
IcedID is a banking Trojan capable of web injects, VM detection and other malicious acts. It consists of two parts- the downloader and the main body that performs all the malicious activity. The main torso is hidden in a PNG image, which is downloaded and decrypted by the downloader.
QBot is also a banking Trojan. It’s a single executable with an embedded DLL( main torso) capable of downloading and operating additional modules that perform malicious activity: web injects, email collecting, password grabbing, etc.
Neither of these malware households are new- we’ve seen them being distributed before via spam campaigns and different downloaders, like the recently taken-down Emotet. However, in the recent campaign we find several modification of the IcedID Trojan.
Technical details Initial infection
The first campaign we called’ DotDat ‘. It distributed ZIP attachments that claimed to be some sort of cancelled functioning or compensation claims with the epithets in the following terms[ document kind( optional )] -[ some digits] -[ date in MMDDYYYY format ]. We presume the dates correspond with the campaign spikes. The ZIP archives contained a malicious MS Excel file with the same name.
The Excel file downloads a malicious payload via a macro( see details below) from a URL with the following terms[ host ]/[ digits ].[ digits ]. dat and executes it. The URL is generated during execution using the Excel function NOW (). The warhead is either the IcedID downloader( Trojan.Win3 2. Ligooc) or QBot packed with a polymorph packer.
Excel macro details( 3e12880c20c41085ea5e249f8eb85ded)
The Excel file contains obfuscated Excel 4.0 macro formulas to download and execute the payload( IcedID or QBot ). The macro produces a warhead URL and calls the WinAPI function URLDownloadToFile to download the payload.
Macro downloads IcedID downloader
After a successful download, the warhead is launched utilizing the EXEC function and Windows Rundll3 2 executable.
Macro starts payload
The spam emails of the second campaign contained link to hacked websites with malicious repositories named “documents.zip”, ” document-XX.zip”, “doc-XX.zip” where XX stands for two random digits. Like in the first campaign, the archives contained an Excel file with a macro that downloaded the IcedID downloader. According to our data, this spam campaign peaked on 17/03/ 2021. By April, the malicious activity had faded away.
Excel macro details( c1 1bad6137c9205d8656714d362cc8e4)
Like in the other case, Excel 4.0 macro formulae and the URLDownloadToFile function are used in this campaign. The main difference in the download component is that the URL is stored in a cell within the malicious file.
Though the URL seems to refer to a file named “summer.gif”, the warhead is an executable , not a GIF image. To execute the warhead, the macro utilizes WMI and regsvr3 2 tools.
Macro starts payload
As we mention above, IcedID consists of two parts- downloader and main torso. The downloader mails some consumer datum( username, MAC address, Windows version, etc .) to the C& C and receives the main body. In the past, the main body was distributed as a shellcode hidden in a PNG image. The downloader gets the image, decrypts the main body in the remembrance and executes it. The main torso maps itself into the memory and starts to perform its malicious actions such as web injects, data exfiltration to the C& C, download and execution of additional warheads, exfiltration of system information and more.
IcedID new downloader
Besides the increase in infection attempts, the IcedID authors also changed the downloader a bit. In previous versions it was compiled as an x86 executable and the malware configuration after decryption contained fake C& C address. We assume this was done to complicate analysis of the samples. In the new version, security threats performers moved from x86 to an x86-64 version and removed the sham C& Cs from the configuration.
Configuration of the age-old version of IcedID downloader
New version configuration
We also find a minor change in the malware’s main body. While it’s still distributed as a PNG image, and the decryption and C& C communication methods remain the same, the authors decided not to use shellcode. Instead, IcedID’s main body is distributed as a standard PE file with some loader-related data in the beginning.
Geography of IcedID attacks
Geography of IcedID downloader detections, March 2021( download)
In March 2021, the greatest number of users attacked by Ligooc( IcedID downloader) were observed in China( 15.88% ), India( 11.59% ), Italy( 10.73% ), the United Country( 10.73%) and Germany ( 8.58% ).
Unlike IcedID, QBot is a single executable with an embedded DLL( main torso) stored into the resource PE section. In order to perform traffic interception, steal passwords, perform web injects and take remote control of the infected system, it downloads additional modules: web inject module, hVNC( remote control module ), email collector, password grabber and others. All the details on Qbot, as well as IoCs, MITRE ATT& CK framework data, YARA rules and hashes relating to this threat are available to users of our Financial Threat Intelligence services.
Geography of Qbot attacks
Geography of QBot attempts, March 2021( download)
In March 2021, QBot was also most active in China( 10.78% ), India( 10.78%) and the United Nation( 4.66% ), but we likewise find it in Russia( 7.60%) and France( 7.60% ).
Indicators of compromise
Trojan.Win3 2. Ligooc
Trojan-Banker.Win3 2. QBot