Questions tagged [ransomware]

Ransomware is a lethal kind of Malware that Encrypts your harddrive(s) and holds them hostage, providing the decryption key if you pay the hostage-taker(s) money (well-known variants are the FBI Virus and the Police Virus).

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1answer
62 views

Suitable hybrid encryption approach?

I need help for my bachelor thesis. I have a general question regarding hybrid encryption in different ransomware. The hybrid encryption often uses symmetric and asymmetric encryption techniques. ...
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432 views

Why can't ransomware practically use RSA to encrypt all files?

I understand that a few ransomware have used an RSA public key to encrypt all files belonging to the victim. This is a bullet-proof system in terms of its security because the private key is always ...
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455 views

Could a quantum computer recover files from ransomware if the attacker doubly encrypted them with RSA-4096?

How would a quantum computer decrypt a file (or find the keys to such a file) if it were encrypted with standard RSA 4096 encryption, but encrypted two times with different keys? The keys are known by ...
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210 views

why ransomwares are still problematic?

There is some points that I don't understand yet about ransomwares : the attacker generally put his bitcoin address in the malware, can this address be used to identify and reach him ? on the ...
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2answers
999 views

Breaking Ransomware encryption

Recent news reports show that the UK's NHS (Nation Health Service) has suffered a major ransomware attack which is also affecting other parts of the world especially Spain and Russia, the effect is to ...
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69 views

Paid decryption scheme and possible attack surface

This is how ransomware can work as far as I understand: Most ransomware works with symmetric encryption on individual files. For each file the script generates a new key. A list is then generated ...
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2answers
101 views

Could a collection of data be engineered to encrypt predictably using standard encryption algorithms?

Thinking about the rather new problem of Cryptolocker and other crypto-randomware, huge amounts of damage are being caused by malicious actors simply using modern encryption algorithms to encrypt a ...
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1answer
596 views

How to detect what crypto-method is used by Filecoder.Q?

I have 2 different images, one original, and one locked by a malware detected by eset as "Win32/Filecoder.Q". How to detect the encryption method that is used and the key, that is not using any ...
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2answers
542 views

Is it possible to decrypt cryptowall-encrypted files? [duplicate]

I am writing regarding a certain ransomware program called cryptowall (prop 4.0). I have lost many documents to this, and as it so happens, I have a few file duplicates before and after they were ...
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1answer
781 views

Understanding ransomware – What makes plain-text-attacks or brute-forcing so hard?

Say I have four files. Two are completely unencrypted, while the other two are the exact same files other than that they have been encrypted with (apparently) the same public key (via a ransomware ...
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1answer
451 views

Help with RSA-2048 crypto ransom virus [closed]

The RSA-2048 Crypto Ransom Virus has devastated me, I tried the backup method, the previous version, the Shadow Explorer, it deleted all my restore points, Its took out 5 HDs and my USB pen that ...
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1answer
714 views

Knowing pre-encryption data, can we find the private key CryptoWall used?

I'm just repurposing a question already asked about Cryptolocker for CryptoWall: "If we know exact contents of some of the files prior to them being encrypted, would it be feasible to use those ...
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739 views

Timing attack on RSA as used by CryptoLocker?

So far I have researched timing attacks on RSA, We all know the ransomware named CryptoLocker uses RSA 2048 bit encryption. Now, is it possible to break the encryption using a timing attack. I have ...
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Knowing pre-encryption data, can we find the private key CryptoLocker used?

One of our users seems to have been hit by CryptoLocker. As a result, he has a hard drive full of encrypted files. The ransom-ware claims to have used public key encryption on the files. If we know ...