Tags: reverse qemu mbr dos
Rating: 5.0
When we run command `file rfc1337.pdf` in linux we get output `rfc1337.pdf: DOS/MBR boot sector`.
After literally the first google *ctf DOS/MBR boot sector* there appeared interesting [writeup](https://ctftime.org/writeup/7765).
QEMU window shows up with a message:
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Next thing we do is:
#### 1. Open gdb
#### 2. qemu-system-x86_64 -s -S -m 512 -fda rfc1337.pdf
#### 3. Continue in *machine* and open *gdb* window
```
$ gdb
(gdb) target remote localhost:1234
(gdb) set architecture i8086
(gdb) break *0x7c00
(gdb) cont
```
##### 4. Finally we execute `dump binary memory result.bin 0x0000 0xffff`
### That's what it all looks like:
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After opening the .bin file in IDA we can see some strings, one of the being **1337TCPHazards** which is the password to unlock the vault:
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### And here is out flag `INTENT{1337H4x0rsKnowHowToBootPDFs}`