nccgroup/asafwConjunto de scripts para trabajar con el firmware de Cisco ASA [empaquetar/desempaquetar, etc.]
Nota preliminar: recomendamos usarlo como parte de asatools, aunque también puede usarse de forma independiente.
asafw es un conjunto de scripts para trabajar con firmware de Cisco ASA. Permite desempaquetar el firmware necesario para depurar con gdb, así como desempaquetarlo/volver a empaquetarlo para habilitar ciertas funciones como:
Las herramientas más útiles son unpack_repack_bin.sh y unpack_repack_qcow2.sh.
Permiten manipular respectivamente los formatos de imagen asa*.bin y asav*.qcow2.
Ambos deben ejecutarse como root al volver a empaquetar el rootfs para
conservar los permisos correctos.
Inicialmente debes modificar asafw/env.sh para adaptarlo a tu entorno. Esto te
permitirá definir las rutas a las herramientas utilizadas por todos los scripts, así como algunas
variables acordes a tu entorno ASA. Ten en cuenta que existe un asadbg/env.sh similar,
pero solo se necesita usar uno para ambos proyectos. Recomendamos que lo añadas a tu ~/.bashrc:```
source /path/to/asafw/env.sh
# unpack_repack_bin.sh
`unpack_repack_bin.sh` se utiliza para desempaquetar/reempaquetar imágenes `asa*.bin` que se usan para hardware real de Cisco ASA (como las series ASA 5500 y 5500-X). El uso completo es:```
$ unpack_repack_bin.sh -h
Usage:
./unpack_repack_bin.sh -i <firmware_file> -o <out_dir> [-f -g -G -a -A -m -b -r -u -l <linabin_dir> -d -e -k]
-h, --help This help menu
-i, --input <firmware_file> What firmware bin to operate on
-o, --output <out_dir> Where to write new firmware
-f, --free-space Remove space from .bin to ensure injections fit
-g, --enable-gdb Set gdb to start on boot
-G, --disable-gdb Stop gdb from starting on boot
-a, --enable-aslr Turn on ASLR
-A, --disable-aslr Turn off ASLR
-m, --inject-gdb Inject gdbserver to run
-b, --debug-shell Inject ssh-triggered debug shell
-H, --lina-hook Inject hooks for monitor lina heap (requires -b)
-r, --root root the bin to get a rootshell on boot
-c, --custom custom?
-n, --n-custom custom?
-q, --gns3-fixup gns?
-u, --unpack-only unpack the firmware and nothing else
-l, --linabins <linabin_dir> destination folder to save lina binaries
-d, --delete-extracted delete files extracted during modification
-e, --delete-original-bin delete the original firmware being modified
-k, --keep-rootfs keep the extracted rootfs on disk
-s, --simple-name use a simple name for the output .bin with just appended '-repacked'
Examples:
./unpack_repack_bin.sh -i /home/user/firmware -o /home/user/firmware_repacked --free-space --enable-gdb --inject-gdb
./unpack_repack_bin.sh -i /home/user/firmware/asa961-smp-k8.bin -f -g -m
./unpack_repack_bin.sh -u -i /home/user/firmware -l /home/user/linabins
./unpack_repack_bin.sh -u -i /home/user/firmware/asa924-k8.bin -k
Supongamos que tenemos estos dos firmware:``` ~/fw$ ls asa924-k8.bin asa981-smp-k8.bin
Si solo quieres extraer el firmware, p. ej. para depurarlo con
[asadbg](https://github.com/nccgroup/asadbg), puedes usar `-u` para solo desempaquetar
y `-k` para conservar solo el rootfs y eliminar los otros archivos extraídos por binwalk
que no necesitas. Ten en cuenta que la carpeta de salida es la misma que la carpeta de entrada
ya que dependemos de binwalk para esto:```
~/fw$ unpack_repack_bin.sh -i . -k -u
[unpack_repack_bin] Directory of firmware detected: .
[unpack_repack_bin] extract_one: asa924-k8.bin
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
75000 0x124F8 SHA256 hash constants, little endian
144510 0x2347E gzip compressed data, maximum compression, from Unix, last modified: 2015-07-15 04:53:23
1501296 0x16E870 gzip compressed data, has original file name: "rootfs.img", from Unix, last modified: 2015-07-15 05:19:52
27168620 0x19E8F6C MySQL ISAM index file Version 4
28192154 0x1AE2D9A Zip archive data, at least v2.0 to extract, name: com/cisco/webvpn/csvrjavaloader64.dll
28773362 0x1B70BF2 Zip archive data, at least v2.0 to extract, name: AliasHandlerWrapper-win64.dll
[unpack_repack_bin] Extracted firmware to /home/user/fw/_asa924-k8.bin.extracted
[unpack_repack_bin] Firmware uses regular rootfs/ dir
[unpack_repack_bin] Extracting /home/user/fw/_asa924-k8.bin.extracted/rootfs/rootfs.img into /home/user/fw/_asa924-k8.bin.extracted/rootfs
[unpack_repack_bin] Keeping rootfs
[unpack_repack_bin] Deleting "/home/user/fw/_asa924-k8.bin.extracted/rootfs.img"
[unpack_repack_bin] Deleting "/home/user/fw/_asa924-k8.bin.extracted/2347E"
[unpack_repack_bin] Deleting "/home/user/fw/_asa924-k8.bin.extracted/1AE2D9A.zip"
[unpack_repack_bin] extract_one: asa981-smp-k8.bin
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
75264 0x12600 SHA256 hash constants, little endian
133120 0x20800 Microsoft executable, portable (PE)
149183 0x246BF gzip compressed data, maximum compression, from Unix, last modified: 2017-01-30 19:33:09
3678112 0x381FA0 gzip compressed data, has original file name: "rootfs.img", from Unix, last modified: 2017-05-10 22:42:05
14838307 0xE26A23 MySQL MISAM compressed data file Version 4
87985870 0x53E8ECE MySQL MISAM compressed data file Version 7
96261881 0x5BCD6F9 Zip archive data, at least v2.0 to extract, name: com/cisco/webvpn/csvrjavaloader64.dll
96890193 0x5C66D51 MySQL ISAM compressed data file Version 5
[unpack_repack_bin] Extracted firmware to /home/user/fw/_asa981-smp-k8.bin.extracted
[unpack_repack_bin] Firmware uses regular rootfs/ dir
[unpack_repack_bin] Extracting /home/user/fw/_asa981-smp-k8.bin.extracted/rootfs/rootfs.img into /home/user/fw/_asa981-smp-k8.bin.extracted/rootfs
[unpack_repack_bin] Keeping rootfs
[unpack_repack_bin] Deleting "/home/user/fw/_asa981-smp-k8.bin.extracted/rootfs.img"
[unpack_repack_bin] Deleting "/home/user/fw/_asa981-smp-k8.bin.extracted/5BCD6F9.zip"
[unpack_repack_bin] Deleting "/home/user/fw/_asa981-smp-k8.bin.extracted/246BF"
Ten en cuenta que los errores como los de abajo que puedas obtener no importan en este caso porque no vas a reempaquetar el firmware:``` cpio: lib/udev/devices/kmem: Function mknod failed: Operation not permitted cpio: lib/udev/devices/net/tun: Function mknod failed: Operation not permitted cpio: lib/udev/devices/loop01: Function mknod failed: Operation not permitted cpio: lib/udev/devices/null: Function mknod failed: Operation not permitted cpio: lib/udev/devices/console: Function mknod failed: Operation not permitted cpio: lib/udev/devices/loop00: Function mknod failed: Operation not permitted 134992 blocks
## Habilitar gdb en el arranque / shell de depuración