Trojan malware specifically designed to locate and exfiltrate wallet.dat files has been active since 2011. These malicious programs scan infected systems for wallet files, often with support for dozens of different cryptocurrencies, and transmit stolen files to command-and-control servers.
If an attacker gains access to an unencrypted wallet.dat file, they can instantly clone the wallet and drain all associated funds. Even if the file is password-encrypted, it can be subjected to offline brute-force attacks.
Finding a wallet.dat file is only the first step. If the wallet is encrypted with a password—which is strongly recommended and is the default in modern Bitcoin Core—the attacker cannot immediately access the funds. However, they can attempt to crack the password offline using powerful tools. In 2021, a standard toolkit for this purpose included: indexofwalletdat 2021
Index of /backup/crypto ----------------------------------------------------------- [ICO] Name Last modified Size ----------------------------------------------------------- [PARENTDIR] Parent Directory 2021-11-12 14:22 - [ ] wallet.dat 2021-04-10 09:15 128K [ ] passwords.txt 2021-05-01 11:45 2K
He downloaded the file. It was encrypted, of course. He ran it through a password recovery tool, feeding it a list of the most common 2013-era passwords. As the software cycled through thousands of variations, Elias stared out his window at the city lights, wondering who had forgotten this. A college kid who bought five Bitcoin for a pizza? A techie who lost interest when the price dropped to $100? Four hours later, the software chirped. Success. The password was summer2013 . Even if the file is password-encrypted, it can
There it was: a file named wallet.dat inside a folder called indexOfWalletDat_2021_manual .
The attack requires an average of 128 × b calls to the padding oracle, where b is the number of bytes in the ciphertext block. While computationally intensive, the attack is feasible, and successful exploits have been published. However, they can attempt to crack the password
Despite its importance, indexing wallet data comes with several challenges and limitations: