During our analysis of malware samples submitted to VirusTotal, we encountered Agpo, which is a ransomware belonging to the Djvu ransomware family. Agpo utilizes encryption to block access to files and adds a new extension (“.agpo”) to the filenames. Furthermore, it generates a ransom note in the form of a text file named “_readme.txt”. For instance, Agpo transforms “a.jpg” into “a.jpg.agpo“, “b.png” into “b.png.agpo“, and so forth. It is important to mention that Djvu ransomware often gets distributed alongside information stealers such as Vidar and RedLine Stealer.
I have compiled an extensive list of potential solutions, tips, and best practices to neutralize the Agpo virus and recover encrypted files. Depending on the circumstances, file recovery may be either straightforward or impossible.
The Agpo ransomware employs a unique key for each victim, with one exception:
- If Agpo fails to establish a connection with the command and control server (C&C Server) before initiating the encryption process, it resorts to the offline key. This particular key is shared among all victims, offering the possibility of decrypting files affected by a ransomware attack.
What is Agpo virus?
☝️ Agpo can be correctly identify as a STOP/DJVU ransomware-type virus.
The Agpo ransomware is a specific kind of threat that encrypted your documents and then forces you to pay to restore them. The image below gives a clear vision of how the files with “.agpo” extension look like:
Agpo File (STOP/DJVU Ransomware)
| Name | Agpo Virus |
| Ransomware family1 | DJVU/STOP2 ransomware |
| Extension | .agpo |
| Ransomware note | _readme.txt |
| Ransom | From $490 to $980 (in Bitcoins) |
| Contact | [email protected], [email protected] |
| Detection | Win32.Virlock.Gen.4, NSIS/Injector.MK, Generic.Trojan.Malicious.DDS |
| Symptoms |
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| Fix Tool |
To remove possible malware infections, scan your PC:
6-day free trial available. |
This message asking payment is for restore files via decryption key:
_readme.txt (STOP/DJVU Ransomware) – The scary alert demanding from users to pay the ransom to decrypt the encoded data contains these frustrating warnings
Agpo ransomware arrives as a set of processes that are meant to perform different tasks on a victim’s computer. One of the first ones being launched is winupdate.exe, a tricky process that displays a fake Windows update prompt during the attack. This is meant to convince the victim that a sudden system slowdown is caused by a Windows update. However, at the same time, the ransomware runs another process (usually named by four random characters) which starts scanning the system for target files and encrypting them. Next, the ransomware deletes Volume Shadow Copies from the system using the following CMD command:
vssadmin.exe Delete Shadows /All /Quiet
Once deleted, it becomes impossible to restore the previous computer state using System Restore Points. The thing is, ransomware operators are getting rid of any Windows OS-based methods that could help the victim to restore files for free. In addition, the crooks modify the Windows HOSTS file by adding a list of domains to it and mapping them to the localhost IP. As a result, the victim will run into a DNS_PROBE_FINISHED_NXDOMAIN error when accessing one of the blocked websites.
We noticed that ransomware attempts to block websites that publish various how-to guides for computer users. It is evident that by restricting specific domains, the crooks are trying to prevent the victim from reaching relevant and helpful ransomware-attack-related information online. The virus also saves two text files on the victim’s computer that provide attack-related details – the victim’s public encryption key and personal ID. These two files are called bowsakkdestx.txt and PersonalID.txt.
After all these modifications, the malware doesn’t stop. Variants of STOP/DJVU tend to drop Vidar password-stealing Trojan on compromised systems. This threat has a lengthy list of capabilities, such as:
- Stealing Steam, Telegram, Skype login / password;
- Stealing cryptocurrency wallets;
- Downloading malware to the computer and running it;
- Stealing browser cookies, saved passwords, browsing history, and more;
- Viewing and manipulating files on victim’s computer;
- Allowing the hackers to perform other tasks on the victim’s computer remotely.
The cryptography algorithm used by DJVU/STOP ransomware family is AES-256. So, if your documents got encrypted with an online decryption key, which is totally distinct. The sad reality is that it is impossible to decrypt the files without the unique key.
In case if Agpo worked in online mode, it is impossible for you to gain access to the AES-256 key. It is stored on a distant server owned by the criminals who promote the Agpo virus.
For receiving decryption key the payment should be $980. To obtain the payment details, the victims are encouraged by the message to contact the frauds by email ([email protected]).
The message by the ransomware states the following information:
ATTENTION! Don't worry, you can return all your files! All your files like photos, databases, documents and other important are encrypted with strongest encryption and unique key. The only method of recovering files is to purchase decrypt tool and unique key for you. This software will decrypt all your encrypted files. What guarantees you have? You can send one of your encrypted file from your PC and we decrypt it for free. But we can decrypt only 1 file for free. File must not contain valuable information. You can get and look video overview decrypt tool: https://we.tl/t-WJa63R98Ku Price of private key and decrypt software is $980. Discount 50% available if you contact us first 72 hours, that's price for you is $490. Please note that you'll never restore your data without payment. Check your e-mail "Spam" or "Junk" folder if you don't get answer more than 6 hours. To get this software you need write on our e-mail: [email protected] Reserve e-mail address to contact us: [email protected] Your personal ID: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
How I was infected?
Ransomware has a various methods to built into your system. But it doesn’t really matter what concrete way was used in your case.
Agpo virus attack following a successful phishing attempt.
- hidden installation along with other apps, especially the utilities that work as freeware or shareware;
- dubious link in spam emails leading to the virus installer
- online free hosting resources;
- using illegal peer-to-peer (P2P) resources for downloading pirated software.
There were cases when the Agpo virus was disguised as some legitimate tool, for example, in the messages demanding to initiate some unwanted software or browser updates. This is typically the way how some online frauds aim to force you into installing the Agpo ransomware manually, by actually making you directly participate in this process.
Surely, the bogus update alert will not indicate that you are going to actually inject the virus. This installation will be concealed under some alert mentioning that allegedly you should update Adobe Flash Player or some other dubious program whatsoever.
Of course, the cracked apps represent the damage too. Using P2P is both illegal and may result in the injection of serious malware, including the Agpo ransomware.
To sum up, what can you do to avoid the injection of the Agpo ransomware into your device? Even though there is no 100% guarantee to prevent your PC from getting damaged, there are certain tips I want to give you to prevent the Agpo penetration. You must be cautious while installing free software today.
Make sure you always read what the installers offer in addition to the main free program. Stay away from opening dubious email attachments. Do not open files from the unknown addressees. Of course, your current security program must always be updated.
The malware does not speak openly about itself. It will not be mentioned in the list of your available programs. However, it will be masked under some malicious process running regularly in the background, starting from the moment when you launch your PC.
How To Remove Agpo Virus?
In addition to encode a victim’s files, the Agpo virus has also started to install the Vidar Stealer on computer to steal account credentials, cryptocurrency wallets, desktop files, and more.
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Download Removal Tool.
You can download GridinSoft Anti-Malware by clicking the button below:
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Run the setup file.
When setup file has finished downloading, double-click on the setup-antimalware-fix.exe file to install GridinSoft Anti-Malware on your PC.
An User Account Control asking you about to allow GridinSoft Anti-Malware to make changes to your device. So, you should click “Yes” to continue with the installation.
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Press “Install” button.
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Once installed, Anti-Malware will automatically run.
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Wait for complete.
GridinSoft Anti-Malware will automatically start scanning your PC for Agpo infections and other malicious programs. This process can take a 20-30 minutes, so I suggest you periodically check on the status of the scan process.
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Click on “Clean Now”.
When the scan has finished, you will see the list of infections that GridinSoft Anti-Malware has detected. To remove them click on the “Clean Now” button in right corner.
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Trojan Killer for special instances
In some certain instances, Agpo ransomware can block the running of setup files of different anti-malware programs. In this situation, you need to utilize the removable drive with a pre-installed antivirus tool.
There is a really little number of security tools that are able to be set up on the USB drives, and antiviruses that can do so in most cases require to obtain quite an expensive license. For this instance, I can recommend you to use another solution of GridinSoft – Trojan Killer Portable. It has a 14-days cost-free trial mode that offers the entire features of the paid version 3. This term will definitely be 100% enough to wipe malware out.
Agpo Removal – Video Guide
How To Decrypt .agpo Files?
How to restore big .agpo files?
Try removing .agpo extension on a few BIG files and opening them. Either the Agpo ransomware read and did not encrypt the file, or it bugged and did not add the filemarker. If your files are very large (2GB+), the latter is most likely. Please, let me know in comments if that will work for you.
The newest extensions released around the end of August 2019 after the criminals made changes. This includes Agvv, Tgpo, Tgvv, etc.
As a result of the changes made by the criminals, STOPDecrypter is no longer supported. It has been removed and replaced with the Emsisoft Decryptor for STOP Djvu Ransomware developed by Emsisoft.
You can download free decryption tool here: Decryptor for STOP Djvu.
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Download and run decryption tool.
Start downloading the decryption tool.
Make sure to launch the decryption utility as an administrator. You need to agree with the license terms that will come up. For this purpose, click on the “Yes” button:
As soon as you accept the license terms, the main decryptor user interface comes up:
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Select folders for decryption.
Based on the default settings, the decryptor will automatically populate the available locations in order to decrypt the currently available drives (the connected ones), including the network drives. Extra (optional) locations can be selected with the help of the “Add” button.
Decryptors normally suggest several options considering the specific malware family. The current possible options are presented in the Options tab and can be activated or deactivated there. You may locate a detailed list of the currently active Options below.
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Click on the “Decrypt” button.
As soon as you add all the desired locations for decryption into the list, click on the “Decrypt” button in order to initiate the decryption procedure.
Note that the main screen may turn you to a status view, letting you know of the active process and the decryption statistics of your data:
The decryptor will notify you as soon as the decryption procedure is completed. If you need the report for your personal papers, you can save it by choosing the “Save log” button. Note that it is also possible to copy it directly to your clipboard and to paste it into emails or messages here if you need to do so.
The Emsisoft Decryptor might display different messages after a failed attempt to restore your agpo files:
✓ Error: Unable to decrypt file with ID: [your ID]
✓ No key for New Variant online ID: [your ID]
Notice: this ID appears to be an online ID, decryption is impossible
✓ Result: No key for new variant offline ID: [example ID]
This ID appears be an offline ID. Decryption may be possible in the future.
It can take a few weeks or months until the decryption key gets found and uploaded to the decryptor. Please follow updates regarding the decryptable DJVU versions here.
✓ Remote name could not be resolved
How to Restore .agpo Files?
In some case Agpo ransomware is not doom for your files…
Agpo ransomware encryption mechanism feature is next: it encrypts every file byte-by-byte, then saves a file copy, deleting (and not overriding!) the original file. Hence, the information of the file location on the physical disk is lost, but the original file is not deleted from the physical disk. The cell, or the sector where this file was stored, can still contain this file, but it is not listed by the file system and can be overwritten by data that has been loaded to this disk after the deletion. Hence, it is possible to recover your files using special software.
Anyway, after realizing it was an online algorithm, it is impossible to retrieve my encrypted files. I also had my backup drive plugged in at the time of the virus, and this was also infected, or so I thought. Every folder within my backup drive had been infected and was encrypted. However, despite losing some important files, I retrieved almost 80% of my 2TB storage.
When I started going through the folders, I noticed the readme.txt ransom note in every folder. I opened some of the folders and found that all files that were not in a subfolder within that folder had been encrypted. However, I found a flaw and glimmer of hope when I went into the subfolders in other folders and found that these files had not been encrypted. Every folder within my c and d drives, including subfolders, had been encrypted, but this was not the case with the backup drive. Having subfolders created within a folder has saved 80% of my data.
As I said, I believe this to be only a small loophole on a backup drive. I’ve since found a further 10 % of my data on another hard drive on a different pc. So my advice is if you use a backup drive, create subfolders. I was lucky, I guess. But I was also unlucky that the virus hit as I was transferring some files from my backup.
Hopefully, this can help some other people in my situation.
Jamie NewlandRecovering your files with PhotoRec
PhotoRec is an open-source program, which is originally created for files recovery from damaged disks, or for files recovery in case if they are deleted. However, as time has gone by, this program got the ability to recover the files of 400 different extensions. Hence, it can be used for data recovery after the ransomware attack
At first, you need to download this app. It is 100% free, but the developer states that there is no guarantee that your files will be recovered. PhotoRec is distributed in a pack with other utility of the same developer – TestDisk. The downloaded archive will have TestDisk name, but don’t worry. PhotoRec files are right inside.
To open PhotoRec, you need to find and open “qphotorec_win.exe” file. No installation is required – this program has all the files it need inside of the archive, hence, you can fit it on your USB drive, and try to help your friend/parents/anyone who was been attacked by DJVU/STOP ransomware.
After the launch, you will see the screen showing you the full list of your disk spaces. However, this information is likely useless, because the required menu is placed a bit higher. Click this bar, then choose the disk which was attacked by ransomware.
After choosing the disk, you need to choose the destination folder for the recovered files. This menu is located at the lower part of the PhotoRec window. The best desicion is to export them on USB drive or any other type of removable disk.
Then, you need to specify the file formats. This option is located at the bottom, too. As it was mentioned, PhotoRec can recover the files of about 400 different formats.
Finally, you can start files recovery by pressing the “Search” button. You will see the screen where the results of the scan and recovery are shown.
Agpo files recovery guide
Frequently Asked Questions
No way. These files are modified by ransomware. The contents of .agpo files are not available until they are decrypted.
If your data remained in the .agpo files are very valuable, then most likely you made a backup copy.
If not, then you can try to restore them through the system function – Restore Point.
All other methods will require patience.
Of course not. Your encrypted files do not pose a threat to the computer. What happened has already happened.
You need GridinSoft Anti-Malware to remove active system infections. The virus that encrypted your files is most likely still active and periodically runs a test for the ability to encrypt even more files. Also, these viruses install keyloggers and backdoors for further malicious actions (for example, theft of passwords, credit cards) often.
In this situation, you need to prepare the memory stick with a pre-installed Trojan Killer.
Have patience. You are infected with the new version of STOP/DJVU ransomware, and decryption keys have not yet been released. Follow the news on our website.
We will keep you posted on when new Agpo keys or new decryption programs appear.
The Agpo ransomware encrypts only the first 150KB of files. So MP3 files are rather large, some media players (Winamp for example) may be able to play the files, but – the first 3-5 seconds (the encrypted portion) will be missing.
You can try to find a copy of an original file that was encrypted:
- Files you downloaded from the Internet that were encrypted and you can download again to get the original.
- Pictures that you shared with family and friends that they can just send back to you.
- Photos that you uploaded on social media or cloud services like Carbonite, OneDrive, iDrive, Google Drive, etc)
- Attachments in emails you sent or received and saved.
- Files on an older computer, flash drive, external drive, camera memory card, or iPhone where you transferred data to the infected computer.
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Brendan SmithAGPO Ransomware — How To Restore & Decrypt Files?
Name: AGPO Virus
Description: The AGPO Virus belongs to the STOP/DJVU family of ransomware infections. This malicious software encrypts various file types, including videos, photos, and documents, which become identifiable by a distinct agpo extension. As a result, the affected files become inaccessible and unusable. Subsequently, the AGPO ransomware demands a ransom payment in Bitcoin from its victims, ranging from $490 to $980.
Operating System: Windows
Application Category: Virus
