On 3-Dec-07, at 4:02 PM, Ansgar -59cobalt- Wiechers wrote:
> On 2007-12-03 Michael R. Martinez wrote:
>> On Mon, 3 Dec 2007 19:40:00 Ansgar -59cobalt- Wiechers wrote:
>>> On 2007-12-02 admin_at_lh.com wrote:
>>>> Get a av that has boot sector protection. Once you've run a scan
>>>> with that, it will clear things out.
>>>
>>> Please explain how boot sector protection is supposed to help
>>> against
>>> malware living in the BIOS. You do realize that it's the BIOS that
>>> executes the boot code, don't you?
>>>
>>> Assuming the BIOS actually is infected (which isn't too clear after
>>> the OP's rather vague description) the appropriate way would be to
>>> replace the BIOS chip or flash a clean BIOS onto it using a
>>> dedicated
>>> device (*not* a PC that is booted with the potentially infected
>>> BIOS). Also examine the supposedly infected harddisk from a clean
>>> system, either by booting some live-CD after cleaning the BIOS or by
>>> attaching the disk to another system (as secondary/external disk).
>>
>> Boot into a disk that scans for virus at boot!
>> Hiren
>> EBCD
>> Etc...
>
> And then what? In case you didn't notice: the BIOS starts the OS on
> that
> disk too, meaning that malware in said BIOS can also manipulate that
> OS
> and thus any software it may run, meaning that despite booting from a
> clean media you still have a (potentially) compromised system.
>
> Regards
> Ansgar Wiechers
> --
> "All vulnerabilities deserve a public fear period prior to patches
> becoming available."
> --Jason Coombs on Bugtraq
Booting from a LiveCD with a current AV and defs might alleviate some
of this concern.
LiveCDs won't be written to during the boot process and shouldn't be
exposed to this
problem.
Flashing the BIOS seems to me to be the most appropriate fix in this
case from your post
it seems to me that your inability to reflash the BIOS may stem from a
jumper or dipswitch
setting on the motherboard that would prevent writing. Check for this
before attempting to
reflash.
Further to this, remove the drive in question from this system and use
a HDD enclosure to
mount the drive USB / Firewire to allow you to scan the drive from a
'known-good' machine.
Best,
Sean Swayze
Received on Dec 04 2007
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