r3shl4k1sh wrote:Alex wrote:Maybe Gapz is "the most complex bootkit seen so far in the wild", but it doesn't change a fact that it is easier to detect and clean it than some older bootkits (see real mebroot for example).
IMO: Once you detect that its there you probably won't leave it alone so why the attacker needs to care about it?
Because AV scanners mostly scan files/folders/startup locations by accessing disk so they can next use signature matcher/other modules working with read data. Inability to remove in most cases is a side effect of filtering used to "hide" actual data from scanners. Quick example from the past. TDL3 injected dll was detected by memory scan by some AV, but infected driver - not detected, as I/O requests filtered by rootkit. Scanner reports to user that he has infection on computer, then scanner "neutralizes" malware in memory, asks for reboot (as it cannot safely unmap all dll code), computer reboots - TDL3 starting up, injecting dll -> scannner again reports about infection. User panics and starts to create topics on internet forums - "invincible virus, please help", "gpu paravirtualization rootkit", "am i infected with blue pill?" etc.
Plus that active "antiremoval feature" give +$$$$ to malware price, as the most users of it are too dumb so they even cannot properly configure their webshits.
As for bootkits overall - they all are mediocre shit, where most advanced setting their I/O filters on the disk port driver level and exploiting computer boot scheme in a different ways (MBR/VBR with variations).