Ftit jiem ilu, iddeċidejt li nagħmel inġinerija inversa tal-firmware tar-router tiegħi billi tuża binwalk.
Xtrajt lili nnifsi . Mhux l-aħjar router, iżda pjuttost biżżejjed għall-bżonnijiet tiegħi.
Kull darba li nixtri router ġdid, ninstalla . Għalxiex? Bħala regola, il-manifatturi ma jimpurtahomx ħafna mill-appoġġ tar-routers tagħhom u maż-żmien is-softwer isir skadut, jidhru vulnerabbiltajiet, u l-bqija, b'mod ġenerali, ikollok l-idea. Għalhekk, nippreferi l-Firmware OpenWRT, li huwa appoġġjat tajjeb mill-komunità ta 'sors miftuħ.
Wara li niżżilt OpenWRT, jien ukoll taħt l-Archer C7 il-ġdid tiegħi mill-websajt uffiċjali u ddeċidejt li janalizzah. Purament għall-gost u tkellem dwar binwalk.
X'inhu binwalk?
hija għodda ta 'sors miftuħ għall-analiżi, l-inġinerija inversa u l-estrazzjoni tal-immaġni tal-firmware.
Maħluq fl-2010 minn Craig Heffner, binwalk jista’ jiskenja immaġini tal-firmware u jsib fajls, jidentifika u estratt immaġini tas-sistema tal-fajls, kodiċi eżekutibbli, arkivji kkompressati, bootloaders u kernels, formati ta’ fajls bħal JPEG u PDF, u ħafna aktar.
Tista' tuża binwalk biex tagħmel reverse engineering tal-firmware biex tifhem kif taħdem. Fittex fajls binarji għal vulnerabbiltajiet, estratt fajls, u fittex backdoors jew ċertifikati diġitali. Tista 'ssib ukoll opcodes għal mazz ta 'CPUs differenti.
Tista' tiġbed immaġini tas-sistema tal-fajls biex tfittex fajls speċifiċi tal-password (passwd, dell, eċċ.) u tipprova tkisser il-hashes tal-password. Tista 'twettaq parsing binarju bejn żewġ fajls jew aktar. Tista 'twettaq analiżi tal-entropija fuq id-dejta biex tfittex dejta kkompressata jew ċwievet ta' encryption kodifikati. Dan kollu mingħajr il-ħtieġa li taċċessa l-kodiċi tas-sors.
B'mod ġenerali, dak kollu li għandek bżonn qiegħed hemm :)
Kif jaħdem binwalk?
Il-karatteristika ewlenija ta 'binwalk hija l-iskannjar tal-firma tiegħu. Binwalk jista’ jiskennja l-immaġni tal-firmware biex ifittex diversi tipi ta’ fajls u sistemi ta’ fajls inkorporati.
Taf l-utilità tal-linja tal-kmand file?
file /bin/bash
/bin/bash: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/l, for GNU/Linux 3.2.0, BuildID[sha1]=12f73d7a8e226c663034529c8dd20efec22dde54, strippedTeam fileiħares lejn l-intestatura tal-fajl u jfittex firma (numru maġiku) biex jiddetermina t-tip tal-fajl. Per eżempju, jekk il-fajl jibda bis-sekwenza ta 'bytes 0x89 0x50 0x4E 0x47 0x0D 0x0A 0x1A 0x0A, jaf li huwa fajl PNG. Fuq Hemm lista ta' firem ta' fajls komuni.
Binwalk jaħdem bl-istess mod. Iżda minflok ma tfittex firem biss fil-bidu tal-fajl, binwalk se jiskennja l-fajl kollu. Barra minn hekk, binwalk jista 'jiġbed fajls misjuba fl-immaġni.
Għodod file и binwalk uża l-librerija libmagic biex tidentifika firem tal-fajls. Iżda binwalk Barra minn hekk jappoġġja lista ta 'firem maġiċi tad-dwana biex tfittex fajls kompressati/zipped, headers tal-firmware, kernels Linux, bootloaders, sistemi ta' fajls eċċ.
Ejja nieħdu pjaċir?
Installazzjoni Binwalk
Binwalk huwa appoġġjat fuq pjattaformi multipli inklużi Linux, OSX, FreeBSD u Windows.
Biex tinstalla l-aħħar verżjoni ta 'binwalk tista' u segwi jew , disponibbli fuq il-websajt tal-proġett.
Binwalk għandu ħafna parametri differenti:
$ binwalk
Binwalk v2.2.0
Craig Heffner, ReFirmLabs
https://github.com/ReFirmLabs/binwalk
Usage: binwalk [OPTIONS] [FILE1] [FILE2] [FILE3] ...
Signature Scan Options:
-B, --signature Scan target file(s) for common file signatures
-R, --raw=<str> Scan target file(s) for the specified sequence of bytes
-A, --opcodes Scan target file(s) for common executable opcode signatures
-m, --magic=<file> Specify a custom magic file to use
-b, --dumb Disable smart signature keywords
-I, --invalid Show results marked as invalid
-x, --exclude=<str> Exclude results that match <str>
-y, --include=<str> Only show results that match <str>
Extraction Options:
-e, --extract Automatically extract known file types
-D, --dd=<type:ext:cmd> Extract <type> signatures, give the files an extension of <ext>, and execute <cmd>
-M, --matryoshka Recursively scan extracted files
-d, --depth=<int> Limit matryoshka recursion depth (default: 8 levels deep)
-C, --directory=<str> Extract files/folders to a custom directory (default: current working directory)
-j, --size=<int> Limit the size of each extracted file
-n, --count=<int> Limit the number of extracted files
-r, --rm Delete carved files after extraction
-z, --carve Carve data from files, but don't execute extraction utilities
-V, --subdirs Extract into sub-directories named by the offset
Entropy Options:
-E, --entropy Calculate file entropy
-F, --fast Use faster, but less detailed, entropy analysis
-J, --save Save plot as a PNG
-Q, --nlegend Omit the legend from the entropy plot graph
-N, --nplot Do not generate an entropy plot graph
-H, --high=<float> Set the rising edge entropy trigger threshold (default: 0.95)
-L, --low=<float> Set the falling edge entropy trigger threshold (default: 0.85)
Binary Diffing Options:
-W, --hexdump Perform a hexdump / diff of a file or files
-G, --green Only show lines containing bytes that are the same among all files
-i, --red Only show lines containing bytes that are different among all files
-U, --blue Only show lines containing bytes that are different among some files
-u, --similar Only display lines that are the same between all files
-w, --terse Diff all files, but only display a hex dump of the first file
Raw Compression Options:
-X, --deflate Scan for raw deflate compression streams
-Z, --lzma Scan for raw LZMA compression streams
-P, --partial Perform a superficial, but faster, scan
-S, --stop Stop after the first result
General Options:
-l, --length=<int> Number of bytes to scan
-o, --offset=<int> Start scan at this file offset
-O, --base=<int> Add a base address to all printed offsets
-K, --block=<int> Set file block size
-g, --swap=<int> Reverse every n bytes before scanning
-f, --log=<file> Log results to file
-c, --csv Log results to file in CSV format
-t, --term Format output to fit the terminal window
-q, --quiet Suppress output to stdout
-v, --verbose Enable verbose output
-h, --help Show help output
-a, --finclude=<str> Only scan files whose names match this regex
-p, --fexclude=<str> Do not scan files whose names match this regex
-s, --status=<int> Enable the status server on the specified portSkennjar tal-immaġni
Nibdew billi nfittxu firem tal-fajls ġewwa l-immaġni (immaġni mis-sit ).
Tmexxi binwalk bil-parametru --firma:
$ binwalk --signature --term archer-c7.bin
DECIMAL HEXADECIMAL DESCRIPTION
------------------------------------------------------------------------------------------
21876 0x5574 U-Boot version string, "U-Boot 1.1.4-g4480d5f9-dirty (May
20 2019 - 18:45:16)"
21940 0x55B4 CRC32 polynomial table, big endian
23232 0x5AC0 uImage header, header size: 64 bytes, header CRC:
0x386C2BD5, created: 2019-05-20 10:45:17, image size:
41162 bytes, Data Address: 0x80010000, Entry Point:
0x80010000, data CRC: 0xC9CD1E38, OS: Linux, CPU: MIPS,
image type: Firmware Image, compression type: lzma, image
name: "u-boot image"
23296 0x5B00 LZMA compressed data, properties: 0x5D, dictionary size:
8388608 bytes, uncompressed size: 97476 bytes
64968 0xFDC8 XML document, version: "1.0"
78448 0x13270 uImage header, header size: 64 bytes, header CRC:
0x78A267FF, created: 2019-07-26 07:46:14, image size:
1088500 bytes, Data Address: 0x80060000, Entry Point:
0x80060000, data CRC: 0xBB9D4F94, OS: Linux, CPU: MIPS,
image type: Multi-File Image, compression type: lzma,
image name: "MIPS OpenWrt Linux-3.3.8"
78520 0x132B8 LZMA compressed data, properties: 0x6D, dictionary size:
8388608 bytes, uncompressed size: 3164228 bytes
1167013 0x11CEA5 Squashfs filesystem, little endian, version 4.0,
compression:xz, size: 14388306 bytes, 2541 inodes,
blocksize: 65536 bytes, created: 2019-07-26 07:51:38
15555328 0xED5B00 gzip compressed data, from Unix, last modified: 2019-07-26
07:51:41Issa għandna ħafna informazzjoni dwar din l-immaġni.
Użi tal-immaġni bħala bootloader (header tal-immaġni fi 0x5AC0 u immaġni bootloader kompressat fuq 0x5B00). Ibbażat fuq il-header uImage f'0x13270, nafu li l-arkitettura tal-proċessur hija MIPS u l-kernel tal-Linux huwa l-verżjoni 3.3.8. U bbażat fuq l-immaġni misjuba fl-indirizz 0x11CEA5, nistgħu naraw li rootfs hija sistema ta' fajls squashfs.
Ejjew issa estratt il-bootloader (U-Boot) billi tuża l-kmand dd:
$ dd if=archer-c7.bin of=u-boot.bin.lzma bs=1 skip=23296 count=41162
41162+0 records in
41162+0 records out
41162 bytes (41 kB, 40 KiB) copied, 0,0939608 s, 438 kB/sPeress li l-immaġni hija kkompressata bl-użu ta 'LZMA, irridu niddekompressawha:
$ unlzma u-boot.bin.lzmaIssa għandna immaġni U-Boot:
$ ls -l u-boot.bin
-rw-rw-r-- 1 sprado sprado 97476 Fev 5 08:48 u-boot.binKif dwar is-sejba tal-valur default għal bootargs?
$ strings u-boot.bin | grep bootargs
bootargs
bootargs=console=ttyS0,115200 board=AP152 rootfstype=squashfs init=/etc/preinit mtdparts=spi0.0:128k(factory-uboot),192k(u-boot),64k(ART),1536k(uImage),14464k@0x1e0000(rootfs) mem=128MU-Boot Ambjent Varjabbli bootargs użati biex jgħaddu parametri lill-kernel Linux. U minn hawn fuq, għandna fehim aħjar tal-memorja flash tal-apparat.
Kif dwar l-estrazzjoni tal-immaġni tal-qalba tal-Linux?
$ dd if=archer-c7.bin of=uImage bs=1 skip=78448 count=1088572
1088572+0 records in
1088572+0 records out
1088572 bytes (1,1 MB, 1,0 MiB) copied, 1,68628 s, 646 kB/sNistgħu niċċekkjaw li l-immaġni ġiet estratta b'suċċess bl-użu tal-kmand file:
$ file uImage
uImage: u-boot legacy uImage, MIPS OpenWrt Linux-3.3.8, Linux/MIPS, Multi-File Image (lzma), 1088500 bytes, Fri Jul 26 07:46:14 2019, Load Address: 0x80060000, Entry Point: 0x80060000, Header CRC: 0x78A267FF, Data CRC: 0xBB9D4F94Il-format tal-fajl uImage huwa bażikament immaġni tal-qalba tal-Linux b'header addizzjonali. Ejja neħħi din l-intestatura biex tikseb l-immaġni finali tal-qalba tal-Linux:
$ dd if=uImage of=Image.lzma bs=1 skip=72
1088500+0 records in
1088500+0 records out
1088500 bytes (1,1 MB, 1,0 MiB) copied, 1,65603 s, 657 kB/sL-immaġni hija kkompressata, allura ejja nispakkjawha:
$ unlzma Image.lzmaIssa għandna immaġni tal-qalba tal-Linux:
$ ls -la Image
-rw-rw-r-- 1 sprado sprado 3164228 Fev 5 10:51 ImageX'nistgħu nagħmlu bl-immaġni tal-qalba? Nistgħu, pereżempju, nagħmlu tfittxija string fl-immaġni u nsibu l-verżjoni tal-kernel tal-Linux u nitgħallmu dwar l-ambjent użat biex tinbena l-kernel:
$ strings Image | grep "Linux version"
Linux version 3.3.8 (leo@leo-MS-7529) (gcc version 4.6.3 20120201 (prerelease) (Linaro GCC 4.6-2012.02) ) #1 Mon May 20 18:53:02 CST 2019Anke jekk il-firmware ġie rilaxxat is-sena l-oħra (2019), hekk kif nikteb dan l-artikolu qed juża verżjoni antika tal-kernel Linux (3.3.8) rilaxxat fl-2012, miġbura b'verżjoni antika ħafna tal-GCC (4.6) ukoll mill-2012. !
(madwar trad. għadek tafda r-routers tiegħek fl-uffiċċju u fid-dar?)
B'għażla --opcodes nistgħu wkoll nużaw binwalk biex infittxu l-istruzzjonijiet tal-magni u niddeterminaw l-arkitettura tal-proċessur tal-immaġni:
$ binwalk --opcodes Image
DECIMAL HEXADECIMAL DESCRIPTION
--------------------------------------------------------------------------------
2400 0x960 MIPS instructions, function epilogue
2572 0xA0C MIPS instructions, function epilogue
2828 0xB0C MIPS instructions, function epilogueXi ngħidu dwar is-sistema tal-fajl tal-għeruq? Minflok ma tiġbed l-immaġni manwalment, ejja nużaw l-għażla binwalk --extract:
$ binwalk --extract --quiet archer-c7.binIs-sistema tal-fajls tal-għeruq kompluta tiġi estratta għal subdirettorju:
$ cd _archer-c7.bin.extracted/squashfs-root/
$ ls
bin dev etc lib mnt overlay proc rom root sbin sys tmp usr var www
$ cat etc/banner
MM NM MMMMMMM M M
$MMMMM MMMMM MMMMMMMMMMM MMM MMM
MMMMMMMM MM MMMMM. MMMMM:MMMMMM: MMMM MMMMM
MMMM= MMMMMM MMM MMMM MMMMM MMMM MMMMMM MMMM MMMMM'
MMMM= MMMMM MMMM MM MMMMM MMMM MMMM MMMMNMMMMM
MMMM= MMMM MMMMM MMMMM MMMM MMMM MMMMMMMM
MMMM= MMMM MMMMMM MMMMM MMMM MMMM MMMMMMMMM
MMMM= MMMM MMMMM, NMMMMMMMM MMMM MMMM MMMMMMMMMMM
MMMM= MMMM MMMMMM MMMMMMMM MMMM MMMM MMMM MMMMMM
MMMM= MMMM MM MMMM MMMM MMMM MMMM MMMM MMMM
MMMM$ ,MMMMM MMMMM MMMM MMM MMMM MMMMM MMMM MMMM
MMMMMMM: MMMMMMM M MMMMMMMMMMMM MMMMMMM MMMMMMM
MMMMMM MMMMN M MMMMMMMMM MMMM MMMM
MMMM M MMMMMMM M M
M
---------------------------------------------------------------
For those about to rock... (%C, %R)
---------------------------------------------------------------Issa nistgħu nagħmlu ħafna affarijiet differenti.
Nistgħu nfittxu fajls ta 'konfigurazzjoni, hashes tal-password, ċwievet kriptografiċi u ċertifikati diġitali. Nistgħu nanalizzaw fajls binarji għal u vulnerabbiltajiet.
Bil и nistgħu anke nħaddmu (jemulaw) eżekutibbli mill-immaġini:
$ ls
bin dev etc lib mnt overlay proc rom root sbin sys tmp usr var www
$ cp /usr/bin/qemu-mips-static .
$ sudo chroot . ./qemu-mips-static bin/busybox
BusyBox v1.19.4 (2019-05-20 18:13:49 CST) multi-call binary.
Copyright (C) 1998-2011 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
Usage: busybox [function] [arguments]...
or: busybox --list[-full]
or: function [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable. Most people will create a
link to busybox for each function they wish to use and BusyBox
will act like whatever it was invoked as.
Currently defined functions:
[, [[, addgroup, adduser, arping, ash, awk, basename, cat, chgrp, chmod, chown, chroot, clear, cmp, cp, crond, crontab, cut, date, dd, delgroup, deluser, dirname, dmesg, echo, egrep, env, expr, false,
fgrep, find, free, fsync, grep, gunzip, gzip, halt, head, hexdump, hostid, id, ifconfig, init, insmod, kill, killall, klogd, ln, lock, logger, ls, lsmod, mac_addr, md5sum, mkdir, mkfifo, mknod, mktemp,
mount, mv, nice, passwd, pgrep, pidof, ping, ping6, pivot_root, poweroff, printf, ps, pwd, readlink, reboot, reset, rm, rmdir, rmmod, route, sed, seq, sh, sleep, sort, start-stop-daemon, strings,
switch_root, sync, sysctl, tail, tar, tee, telnet, test, tftp, time, top, touch, tr, traceroute, true, udhcpc, umount, uname, uniq, uptime, vconfig, vi, watchdog, wc, wget, which, xargs, yes, zcatKbir! Iżda jekk jogħġbok innota li l-verżjoni BusyBox hija 1.19.4. Din hija verżjoni antika ħafna ta' BusyBox, maħruġa f'April 2012.
Allura TP-Link jirrilaxxa immaġni tal-firmware fl-2019 billi juża softwer (GCC toolchain, kernel, BusyBox, eċċ.) mill-2012!
Issa tifhem għaliex dejjem ninstalla OpenWRT fuq ir-routers tiegħi?
Dak mhux kollox
Binwalk jista 'wkoll iwettaq analiżi tal-entropija, jistampa dejta tal-entropija mhux ipproċessat, u jiġġenera graffs tal-entropija. Tipikament, entropija akbar hija osservata meta l-bytes fl-immaġni huma każwali. Dan jista 'jfisser li l-immaġni fiha fajl encrypted, kompressat jew offuskat. Ċavetta ta' encryption iebsa? Għaliex le.
Nistgħu wkoll nużaw il-parametru --raw biex issib sekwenza ta' byte mhux ipproċessat apposta f'immaġni jew parametru --hexdump biex twettaq hex dump li tqabbel żewġ fajls ta' input jew aktar.
jista 'jiġi miżjud ma' binwalk jew permezz ta 'fajl tal-firma tad-dwana speċifikat fuq il-linja tal-kmand bl-użu tal-parametru --magic, jew billi żżidhom mad-direttorju $ HOME / .config / binwalk / magic.
Tista' ssib aktar informazzjoni dwar binwalk fuq .
estensjoni binwalk
Hemm binwalk, implimentat bħala modulu Python li jista 'jintuża minn kwalunkwe skript Python biex iwettaq b'mod programmatiku skannjar binwalk, u l-utilità tal-linja tal-kmand binwalk tista' tkun kważi kompletament duplikata b'żewġ linji biss ta 'kodiċi Python!
import binwalk
binwalk.scan()Bl-użu tal-API Python tista 'wkoll toħloq biex tikkonfigura u tespandi binwalk.
Hemm ukoll u verżjoni sħaba .
Allura għaliex ma tniżżel l-immaġni tal-firmware mill-Internet u tipprova binwalk? Inwiegħed li tieħu pjaċir ħafna :)
Sors: www.habr.com