security/xorsearch 1.11.1 DragonFly

XORSearch is a program to search for a given string in an XOR or ROL encoded binary file. An XOR encoded binary file is a file where some (or all) bytes have been XORed with a constant value (the key). A ROL (or ROR) encoded file has it bytes rotated by a certain number of bits (the key). XOR and ROL/ROR encoding is used by malware programmers to obfuscate strings like URLs.

XORSearch will try all XOR keys (0 to 255) and ROL keys (1 to 7) when searching. I programmed XORSearch to include key 0, because this allows to search in an unencoded binary file (X XOR 0 equals X).

If the search string is found, XORSearch will print it until the 0 (byte zero) is encountered or until 50 characters have been printed, which ever comes first. 50 is the default value, it can be changed with option -l. Unprintable characters are replaced by a dot.