base64 in database

[sattvhelp]

ok, im slowly working my way through this, following numerous online guides, and racking up the google air miles.

just about EVERY post that asks about any base64 code within vbulletin files, seems to be met with the default answer from vbulletin staff that 'vbulletin doesnt contain any base64 code, its been added by hackers, redownload new files'

Ive downloaded new files, and before even unzipping them, have found the following INSIDE the default vbulletin file attachment.php

$filedata = vb_base64_decode('R0lGODlhAQABAIAAAMDAwAAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==');

As someone who is not an expert, and following guidance telling me that i should have NO base64 code AT ALL in ANY vbulletin file, i dont know how i should proceed next, as i have found around a dozen default files that contain base64

--------------- Added [DATE]1494088047[/DATE] at [TIME]1494088047[/TIME] ---------------

Originally Posted by Kane@airrifle

ACP/Plugin manager: Check to see if you have init_startup in Product : Vbulletin. If you do that is likely the backdoor.

Some background: https://www.vbulletin.com/forum/foru...-patch-level-4

This was indeed tucked away, and has since been removed. After removing it i cleared the system cache, and this has also caused the entire entry to be removed from the database