Catch URIError Exceptions on Malformed URI Sequences

[0xSobky]

Hey @wisec,

Malformed URI sequences can cause the decodeURI and decodeURIComponent functions to throw a URIError exception. This causes the entire deobfuscation attempt to fail as a result:

$ ./jstillery_cli.js obfuscated.js
URIError: URI malformed
    at decodeURIComponent (<anonymous>)
    at ast_reduce ([REDACTED]/src/jstiller.js:1612:45)
    at ast_reduce_scoped ([REDACTED]/src/jstiller.js:840:14)
    at ast_reduce ([REDACTED]/src/jstiller.js:1098:23)
    at ast_reduce_scoped ([REDACTED]/src/jstiller.js:840:14)
    at Array.map (<anonymous>)
    at Object.ast_reduce [as deobfuscate] ([REDACTED]/src/jstiller.js:1091:26)
    at Object.<anonymous> ([REDACTED]/jstillery_cli.js:61:16)
    at Module._compile (module.js:660:30)
    at Object.Module._extensions..js (module.js:671:10)
Original:
====================
eval(String.fromCharCode(97,108,101,114,116))(1);decodeURIComponent('%xx');

====================
____________________
Deobfuscated Code
eval(String.fromCharCode(97, 108, 101, 114, 116))(1);
decodeURIComponent('%xx');

The output after the fix is:

Original:
====================
eval(String.fromCharCode(97,108,101,114,116))(1);decodeURIComponent('%xx');

====================
____________________
Deobfuscated Code
alert;(1);
decodeURIComponent('%xx');

Cheers!

[wisec]

Thanks!