tool mini-review: radare2

[If you’re already familiar with radare2, and it’s firmware — and EBC — abilities, then skip this blog.]

In 2014, Anton Kochkov gave an interesting talk: “Reversing firmware using radare2”. The scope of ‘firmware’ used in the presentation includes a wide range, UEFI, BIOS, to peripherals. Actually, the talk isn’t that interesting for information on radare, since most of the fun stuff were in the demos, not shown in the slides. IMO, the most interesting parts are the first half of the slides, before radare is introduced, where the speaker gives an interesting overview of some known silicon and firmware attacks. The last few slides mention a few other firmware security tools besides radare: UEFI Tool, BIOS Extract, FlashROM, Bus Pirate, and a few QEMU-based emulators. The presentation has MANY pointers to more information, I’ve queued up about a dozen things to read as a result of reading this. 😦

Radare is an open source reverse engineering tool, it has GUI and command line interfaces. It is peer of IDA, disassembling code is the main focus.

It supports many architectures: 6502, 8051, CRIS, H8/300, LH5801, T8200, arc, arm, avr, bf, blackfin, csr, dalvik, dcpu16, gameboy, i386, i4004, i8080, m68k, malbolge, mips, mips, msil, nios II, powerpc, rar, sh, snes, sparc, tms320 (c54x c55x c55+), V810, x86-64, and zimg. It supports many file formats: bios, dex, elf, elf64, filesystem, java, fatmach0, mach0, mach0-64, MZ, PE, PE+, TE, COFF, plan9, bios, dyldcache, Gameboy and Nintendo DS ROMs. It supports many operating systems: Android, GNU/Linux, [Net|Free|Open]BSD, iOS, OSX, QNX, w32, w64, Solaris, Haiku, and FirefoxOS. It has multiple language bindings: Vala/Genie, Python (2, 3), NodeJS, LUA, Go, Perl, Guile, php5, newlisp, Ruby, Java, and OCAML.

Radare’s GUIs aside, the r2 command line UI offers nice use of colors and graphics to correlate assembly language features, somewhat like how Scapy does with network packets.

Radare definitely looks like a useful tool for firmware researchers. A Google Search for radare and firmware results in lots of existing research and tutorials. Apparently, I’m the last person to learn about radare. 😦

Best yet: radare supports EFI Bytecode (EBC)!! They added EBC support, started about 2 years ago. Search for TARGET_EBC in the code. They don’t list EBC in their architecture list (above), so I’ve yet to see how well it works.

Note also in above list, they support TE executable images, and some level of “BIOS” support (yet to determine what that means).

[I was about to write a paragarph about how UEFI Forum should sponsor EBC support in LLVM, so that radare can benefit from LLVM’s intermediate representation, as well as providing an alternative compiler to the single EBC-targetting compiler, the COMMERCIAL-ONLY Intel C Compiler. But since radare already manually added EBC support to their tool, the need for LLVM as a target is no longer as important, UEFI Forum could target either GCC or LLVM, since radare has dealt with EBC themselves. We still need an alternative, non-commercial, open source EBC-targetting C compiler, though!]

[[UPDATE: The above paragraph is wrong, w/r/t radare and LLVM: Capstone is the RE tool that uses LLVM intermediate language, not radare, sorry. ]]

More Information:

Click to access h2hc2014-reversing-firmware-radare-slides.pdf

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