AGVV Ransomware (.agvv File Extension)

What is Agvv?

The Agvv virus, a type of ransomware within the STOP/Djvu family, specifically targets your finances. This malware encrypts your files using a sophisticated cipher and then demands a ransom (approximately $1000) for decryption. To thwart any alternative decryption methods, the Agvv virus implements various system modifications.

These alterations primarily affect security settings. Initially, the malware disables Microsoft Defender and blocks any third-party security software present. Subsequently, it modifies Group Policies to prevent the execution of antivirus program installation files. The ultimate maneuver involves restricting access to websites offering insights on file decryption and malware eradication. Such changes can impede future PC operations, underscoring the importance of their prompt reversal.

Regarding the distribution of Agvv ransomware, its emergence isn't coincidental; it's often bundled with seemingly innocuous software. "Free" versions of inherently paid applications, crafted by anonymous developers, serve as a common vector. During the modification process, these creators can embed any malicious payload into the program's executable, ranging from spyware and coin miners to ransomware or data stealers. Sidestepping such hazards is advisable, particularly given the legal challenges in holding the culprits accountable.

Agvv Encryption process

The Agvv uses the Salsa20 encryption algorithm. That is not the strongest method, but it still provides an overwhelming amount of possible decryption keys. To brute force the 78-digit number of keys, you need 3.5 unvigintillion years (1*10^65), even if you use the most powerful regular PC. Quantum computers can show a bit better results, but it is still too slow to get your files back while you are alive.

The exact algorithm of encryption is next: malware scans each folder for the files it is able to encrypt. Then, when it finds the target, it makes a copy of your file, removes the original one, encrypts the copy and leaves it instead of the removed original. Such a procedure is done to prevent the situation when you have already opened the file, so ransomware is not able to read it because of the Windows restrictions. To each encrypted copy, the virus adds the specific extension - ".agvv". Then, ransomware creates a _readme.txt file in the folder where the encrypted file is located, and goes to the next folder.

Such an encryption method can be exploited for file recovery. Since the original file is deleted, you may try to recover it using the file recovery tools. The less time is passed - the bigger the chance to get your files back, so hurry up!

Another specific moment that can help you to use the files even after the encryption is the fact that Agvv ransomware encrypts only the first 150KB of each file. Hence, you can try to run a big file, such as video or music, without the encryption. Similar feature also works with other ransomware families - Dharma, Conti and Makop encrypt the same 150KB.

Agvv note:

Ransom note is the same for the whole STOP/DJVU family. In fact, it is one of the main signs of to which family the certain ransomware belongs. Here is the typical note for STOP/Djvu family:

External Links:

🔗 HowToFix.Guide: How To Decrypt .agvv Files?

Indicators of Compromise(IOC)

File Name	MD5	File Size
📜 SAMPLE.EXE	e7dce44fd1c02623719da154a73530b2	6172531
📜 SAMPLE.EXE	8498a90e5079ab50533e2471231b044e	277504
📜 SAMPLE.EXE	622e7c9379b9c65e8ac368606586fbec	280576
📜 SAMPLE.EXE	ddb1ec135c4010bba26c01cc82c4b324	1273856
📜 SAMPLE.EXE	8dd2b3621a602482286f8e3fbd31b567	1273856
📜 SAMPLE.EXE	0a9e0021bb0cf7315601291d34fa20df	799744
📜 SAMPLE.EXE	5f01b8d33d1762badb20d4220ac33e0b	801280
📜 SAMPLE.EXE	d74b78f8e04f9107101ddca79f548998	799232
📜 SAMPLE.EXE	8afd319994d262137b43aeb6a74ad51e	799232
📜 SAMPLE.EXE	40b203851c4c24adc848bc6f1f3e7cc2	809984