How to eliminate TimbreStealer malware from the operating system

What kind of malware is TimbreStealer?

TimbreStealer is a piece of malicious software designed to steal information. It was first observed being proliferated through email spam campaigns in the autumn of 2023 and is still in active distribution as of February 2024. This malware was noted being used to target users in Mexico exclusively.

Although not definitive, some evidence links the threat actors behind TimbreStealer with campaigns spreading the Mispadu banking trojan. However, it appears that these cyber criminals are no longer using Mispadu.

TimbreStealer malware overview

TimbreStealer is a sophisticated malware that is highly obfuscated. Known attacks employed custom-built loaders to infiltrate TimbreStealer into systems. This stealer checks whether it is executed on a virtual machine or in a sandbox environment. It has anti-detection and anti-debugging capabilities.

TimbreStealer also searches for files related to anti-virus software. This malware is modular, and it utilizes multiple modules and submodules. The program may display a decoy document to redirect victims' attention from its malicious behavior.

At the time of research, following infiltration, TimbreStealer began by collecting relevant device data, including detailed geolocation information. To elaborate, it verified whether the operating system's language was not Russian and whether the timezone matched Mexico.

TimbreStealer can extract and exfiltrate data from Google Chrome, Mozilla Firefox, and Microsoft Edge browsers. Primarily, the malware seeks browsing histories and saved log-in credentials (usernames/passwords).

The program aims to obtain information related to the OneDrive and Dropbox file hosting services, as well as the Mozilla Thunderbird email client. TimbreStealer checks for URLs of interest, which include the aforementioned cloud storage services, Amazon, Apple, Facebook, Google, LinkedIn, PayPal, X (more commonly known by its former name – Twitter), and others.

The stealer searches for remote access software, but the purpose behind this is currently unclear. Some malicious programs can self-spread to remotely connected devices, which could be a future goal of this malware.

TimbreStealer also browses numerous system and user folders; the latter include desktop, documents, downloads, and others. The stealer seeks various files, including backups, databases, Internet security certificates, text documents, spreadsheets, etc. Targeted formats consist of .bak, .cer, .cmp, .dat, .db, .dbf, .fbk, .fdb, .mdf, .ods, .txt, .xls, .xlsx, .xml, and .zuhpgmcf. The last one – ".zuhpgmcf" – is an unknown file format; it could be a file(s) made by TimbreStealer itself.

It is noteworthy that malware developers often improve upon their software and methodologies. Therefore, potential future versions of TimbreStealer could have additional/different functionalities and features.

To summarize, the presence of software like TimbreStealer on devices can lead to severe privacy issues, financial losses, and identity theft.

Threat Summary:

Name	TimbreStealer virus
Threat Type	Trojan, stealer, password-stealing virus, banking malware, spyware.
Detection Names	Avast (Win32:Evo-gen [Trj]), Combo Cleaner (Trojan.GenericKD.71783999), ESET-NOD32 (A Variant Of Win32/Kryptik.HVWT), Kaspersky (Trojan.Win32.Agent.xbltal), Microsoft (PWS:Win32/Zbot!ml), Full List Of Detections (VirusTotal)
Symptoms	Trojans are designed to stealthily infiltrate the victim's computer and remain silent, and thus no particular symptoms are clearly visible on an infected machine.
Distribution methods	Spam emails, malicious online advertisements, social engineering, software 'cracks'.
Damage	Stolen passwords and banking information, identity theft, the victim's computer added to a botnet.
Malware Removal (Windows)	To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. ▼ Download Combo Cleaner To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Stealer-type malware examples

We have investigated countless malware samples; XSSLite, 44Caliber, Spock, and VietCredCare are merely a few of our newest articles on stealers.

Malicious software is not limited to its classification, and data-stealing abilities are common for various types. However, regardless of whether malware targets data or what information it seeks – its presence on a system threatens device integrity and user safety. Hence, all threats must be eliminated immediately upon detection.

How did TimbreStealer infiltrate my computer?

As mentioned in the introduction, TimbreStealer has been proliferated via spam campaigns since the autumn of 2023. The malicious emails used generic invoice-themed lures and ones relating to "Comprobante Fiscal Digital por Internet" (CDFI) – the standard electronic invoice for tax reports in Mexico.

The emails boasted subjects such as "Recibió una Factura. Folio Fiscal: 050e4105-799f-4d17-a55d-60d1f9275288", "Recibió un Comprobante Fiscal Digital (CFDI). Folio Fiscal: fcd7bf2f-e800-4ab3-b2b8-e47eb6bbff8c", etc. These letters contained links that redirected users to malignant websites intended to deceive them into downloading an infectious ZIP archive.

The sites employed geo-blocking techniques to allow only users based in Mexico; visitors from outside the region were presented with a blank PDF document instead. The known virulent archives were named "CFDI_930209.zip" and "FACTURA_560208.zip" (other filenames are not unlikely). Once the victim opened the downloaded ZIP and clicked the .URL file – TimbreStealer's infection chain was initiated.

However, it is pertinent to mention that other lures or distribution methods are possible. Malicious software is commonly disguised as or bundled with regular program/media files. They come in various formats, e.g., archives (ZIP, RAR, etc.), executables (.exe, .run, etc.), documents (PDF, Microsoft Office, Microsoft OneNote, etc.), JavaScript, and so on.

The most widely used proliferation techniques include: malicious attachments/links in spam (e.g., emails, DMs/PMs, social media posts, etc.), drive-by (stealthy and deceptive) downloads, online scams, malvertising, untrustworthy download sources (e.g., freeware and third-party websites, Peer-to-Peer sharing networks, etc.), pirated programs/media, illegal software activation ("cracking") tools, and fake updates.

Some malicious programs can even self-spread through local networks and removable storage devices (e.g., external hard drives, USB flash drives, etc.).

How to avoid installation of malware?

It is essential to treat incoming emails and other messages with caution. Attachments or links present in dubious/irrelevant mail must not be opened, as they can be virulent. We recommend being careful while browsing since fraudulent and malicious online content usually appears legitimate and innocuous.

Furthermore, all downloads must be made from official and verified sources. Another recommendation is to activate and update programs using functions/tools provided by genuine developers, as those obtained from third-parties may contain malware.

It is paramount for device/user safety to have a reputable anti-virus installed and kept up-to-date. Security software must be used to run regular system scans and to remove threats and issues. If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.

Screenshot of a spam email spreading the TimbreStealer stealer (image source – Cisco Talos):

Instant automatic malware removal: Manual threat removal might be a lengthy and complicated process that requires advanced IT skills. Combo Cleaner is a professional automatic malware removal tool that is recommended to get rid of malware. Download it by clicking the button below:
▼ DOWNLOAD Combo Cleaner By downloading any software listed on this website you agree to our Privacy Policy and Terms of Use. To use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by Rcs Lt, the parent company of PCRisk.com read more.

Quick menu:

• What is TimbreStealer?
• STEP 1. Manual removal of TimbreStealer malware.
• STEP 2. Check if your computer is clean.

How to remove malware manually?

Manual malware removal is a complicated task - usually it is best to allow antivirus or anti-malware programs to do this automatically. To remove this malware we recommend using Combo Cleaner Antivirus for Windows.

If you wish to remove malware manually, the first step is to identify the name of the malware that you are trying to remove. Here is an example of a suspicious program running on a user's computer:

If you checked the list of programs running on your computer, for example, using task manager, and identified a program that looks suspicious, you should continue with these steps:

Download a program called Autoruns. This program shows auto-start applications, Registry, and file system locations:

Restart your computer into Safe Mode:

Windows XP and Windows 7 users: Start your computer in Safe Mode. Click Start, click Shut Down, click Restart, click OK. During your computer start process, press the F8 key on your keyboard multiple times until you see the Windows Advanced Option menu, and then select Safe Mode with Networking from the list.

Video showing how to start Windows 7 in "Safe Mode with Networking":

Windows 8 users: Start Windows 8 is Safe Mode with Networking - Go to Windows 8 Start Screen, type Advanced, in the search results select Settings. Click Advanced startup options, in the opened "General PC Settings" window, select Advanced startup.

Click the "Restart now" button. Your computer will now restart into the "Advanced Startup options menu". Click the "Troubleshoot" button, and then click the "Advanced options" button. In the advanced option screen, click "Startup settings".

Click the "Restart" button. Your PC will restart into the Startup Settings screen. Press F5 to boot in Safe Mode with Networking.

Video showing how to start Windows 8 in "Safe Mode with Networking":

Windows 10 users: Click the Windows logo and select the Power icon. In the opened menu click "Restart" while holding "Shift" button on your keyboard. In the "choose an option" window click on the "Troubleshoot", next select "Advanced options".

In the advanced options menu select "Startup Settings" and click on the "Restart" button. In the following window you should click the "F5" button on your keyboard. This will restart your operating system in safe mode with networking.

Video showing how to start Windows 10 in "Safe Mode with Networking":

Extract the downloaded archive and run the Autoruns.exe file.

In the Autoruns application, click "Options" at the top and uncheck "Hide Empty Locations" and "Hide Windows Entries" options. After this procedure, click the "Refresh" icon.

Check the list provided by the Autoruns application and locate the malware file that you want to eliminate.

You should write down its full path and name. Note that some malware hides process names under legitimate Windows process names. At this stage, it is very important to avoid removing system files. After you locate the suspicious program you wish to remove, right click your mouse over its name and choose "Delete".

After removing the malware through the Autoruns application (this ensures that the malware will not run automatically on the next system startup), you should search for the malware name on your computer. Be sure to enable hidden files and folders before proceeding. If you find the filename of the malware, be sure to remove it.

Reboot your computer in normal mode. Following these steps should remove any malware from your computer. Note that manual threat removal requires advanced computer skills. If you do not have these skills, leave malware removal to antivirus and anti-malware programs.

These steps might not work with advanced malware infections. As always it is best to prevent infection than try to remove malware later. To keep your computer safe, install the latest operating system updates and use antivirus software. To be sure your computer is free of malware infections, we recommend scanning it with Combo Cleaner Antivirus for Windows.

Frequently Asked Questions (FAQ)

My computer is infected with TimbreStealer malware, should I format my storage device to get rid of it?

Malware removal rarely necessitates formatting.

What are the biggest issues that TimbreStealer malware can cause?

The threats an infection poses depend on the malicious program's functionalities and the cyber criminals' modus operandi. TimbreStealer is a sophisticated information stealer. Infections of this kind can lead to severe privacy issues, financial losses, and identity theft.

What is the purpose of TimbreStealer malware?

Malware is primarily used for profit. However, infections can be motivated by the attackers seeking amusement, personal grudges, process disruption (e.g., websites, services, companies, etc.), hacktivism, and political/geopolitical reasons.

How did TimbreStealer malware infiltrate my computer?

TimbreStealer has been noted being spread via email spam campaigns targeting users in Mexico. These letters utilized invoice and tax related lures. However, other distribution methods are possible.

Generally, malware is proliferated via drive-by downloads, spam (e.g., emails, PMs/DMs, SMSes, etc.), untrustworthy download sources (e.g., freeware and free file-hosting sites, P2P sharing networks, etc.), pirated content, illegal software activation tools ("cracks"), fake updates, online scams, and malvertising. What is more, some malicious programs can self-spread via local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner is capable of detecting and eliminating nearly all known malware infections. It must be stressed that performing a full system scan is crucial since high-end malicious programs typically hide deep within systems.

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