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VBF versions 2.4+
Posted: Sat Feb 22, 2025 6:53 am
by bstddc5
has anyone had luck figuring out what kind of encryption/compression is used on the newer vbf formats? short of disassembling IDA im running out of leads on where to find answers.
Re: VBF versions 2.4+
Posted: Tue Feb 25, 2025 2:23 am
by Gatecrasher
Got any examples? I've got a few 2.4 files but they're not encrypted or compressed. They're for 2017-ish.
Re: VBF versions 2.4+
Posted: Wed Feb 26, 2025 8:57 am
by bstddc5
here is a 2.4 version
Re: VBF versions 2.4+
Posted: Thu Feb 27, 2025 1:14 am
by Gatecrasher
Check this out.
I have a command line tool I've been using, and while it extracted your file, it looked like gibberish. Block sizes were weird and there was high entropy. Just like you said. Compressed and/or encrypted.
So I did a little digging and found this.
https://github.com/smartgauges/qvbf
Direct link to exe:
https://github.com/smartgauges/qvbf/raw ... 2/qvbf.exe
It's Russian, so take it with a grain of salt. But it seems to work. The program output explicitly says it uncompressed the block. The resulting block I extracted is a more normal size (16384 instead of 12979), and I can see plain text data in the boot block referencing SHA1 hashes.
Re: VBF versions 2.4+
Posted: Thu Feb 27, 2025 3:29 am
by bstddc5
GOOD FIND! it looks like there's lzss decompression going on. ill give it a look and compare against some files i already have for accuracy and report back.
Re: VBF versions 2.4+
Posted: Thu Feb 27, 2025 10:30 am
by bstddc5
good news it works and seems to match up. bad news the output format is terrible at best. trying to patch together 100+ blocks on some files sounds like a terrible time.
Re: VBF versions 2.4+
Posted: Fri Feb 28, 2025 12:41 am
by Gatecrasher
I thought doing 30 on my 2.7 EcoBoost was bad. 100 would be super annoying.
Check out the attachment. I used the Linux cat command to merge them. Took all of 5 minutes, including pre-processing the file list into a text string.
https://stackoverflow.com/questions/103 ... nux-system
I'd recommend spot checking it to make sure I didn't get something out of order. I just used the default order that qvbf spit them out in, so that could be wrong too. I think the overall concept is sound though.
Re: VBF versions 2.4+
Posted: Fri Feb 28, 2025 2:18 pm
by antus
That's a good method, that's how I make stacked bins for other purposes too.