Crate xgadget[−][src]
Fast, parallel, cross-variant ROP/JOP gadget search for x86 (32-bit) and x64 (64-bit) binaries. Uses the iced-x86 disassembler library.
Current state: decent test coverage, but still in beta. Issues/PRs welcome :)
About
To the best of my knowledge, xgadget
is the first gadget search tool to have these features:
- JOP search uses instruction semantics - not hardcoded regex for individual encodings
- Optionally filter to JOP "dispatcher" gadgets with flag
--dispatcher
- Optionally filter to JOP "dispatcher" gadgets with flag
- Finds gadgets that work across multiple variants of a binary (e.g. different program or compiler versions)
- Full-match - Same instruction sequence, same program counter: gadget fully re-usable.
- E.g.
pop rsp; add [rax-0x77], cl; ret ------------------------------------- [ 0xc748d ]
- E.g.
- Partial-match - Same instruction sequence, different program counter: gadget logic portable.
- E.g.
pop rsp; add [rax-0x77], cl; ret; --- [ 'bin_v1.1': 0xc748d, 'bin_v1.2': 0xc9106 ]
- E.g.
- This is entirely optional, you're free to run this tool on a single binary.
- Full-match - Same instruction sequence, same program counter: gadget fully re-usable.
- The stack pointer is explicitly colored in terminal output, for workflow convenience.
Other features include:
- Both library API and CLI tool
- Supports ELF32, ELF64, PE32, PE32+ [1], and raw files
- Parallel across available cores [2], whether searching a single binary or multiple variants
- CI/CD for automated integration test and binary releases (Linux, 64-bit) [3]
- Statistical benchmark harness for performance tuning [4]
- 8086/x86/x64 only, uses a speed-optimized disassembly backend [5]
API Usage
Find gadgets:
use xgadget; let max_gadget_len = 5; // Search single binary let search_config = xgadget::SearchConfig::DEFAULT; let bin_1 = xgadget::Binary::from_path_str("/path/to/bin_v1").unwrap(); let bins = vec![bin_1]; let gadgets = xgadget::find_gadgets(&bins, max_gadget_len, search_config).unwrap(); let stack_pivot_gadgets = xgadget::filter_stack_pivot(&gadgets); // Search for cross-variant gadgets, including partial matches let search_config = xgadget::SearchConfig::DEFAULT | xgadget::SearchConfig::PART; let bin_1 = xgadget::Binary::from_path_str("/path/to/bin_v1").unwrap(); let bin_2 = xgadget::Binary::from_path_str("/path/to/bin_v2").unwrap(); let bins = vec![bin_1, bin_2]; let cross_gadgets = xgadget::find_gadgets(&bins, max_gadget_len, search_config).unwrap(); let cross_reg_pop_gadgets = xgadget::filter_reg_pop_only(&cross_gadgets);
Custom filters can be created using the GadgetAnalysis
object and/or functions from the semantics
module.
How the above filter_stack_pivot
function is implemented:
use rayon::prelude::*; use iced_x86; use xgadget::{Gadget, GadgetAnalysis}; /// Parallel filter to gadgets that write the stack pointer pub fn filter_stack_pivot<'a>(gadgets: &[Gadget<'a>]) -> Vec<Gadget<'a>> { gadgets .par_iter() .filter(|g| { let regs_overwritten = GadgetAnalysis::new(&g).regs_overwritten(); if regs_overwritten.contains(&iced_x86::Register::RSP) || regs_overwritten.contains(&iced_x86::Register::ESP) || regs_overwritten.contains(&iced_x86::Register::SP) { return true; } false }) .cloned() .collect() }
CLI Usage
Run xgadget --help
:
xgadget v0.5.0 About: Fast, parallel, cross-variant ROP/JOP gadget search for x86/x64 binaries. Cores: 8 logical, 8 physical USAGE: xgadget [FLAGS] [OPTIONS] <FILE(S)>... FLAGS: -t, --att Display gadgets using AT&T syntax [default: Intel syntax] -c, --check-sec Run checksec on the 1+ binaries instead of gadget search -d, --dispatcher Filter to potential JOP 'dispatcher' gadgets [default: all] -e, --extended-fmt Print in terminal-wide format [default: only used for partial match search] -h, --help Prints help information --inc-call Include gadgets containing a call [default: don't include] --inc-imm16 Include '{ret, ret far} imm16' (e.g. add to stack ptr) [default: don't include] -j, --jop Search for JOP gadgets only [default: ROP, JOP, and SYSCALL] -n, --no-color Don't color output [default: color output] --param-ctrl Filter to gadgets that control function parameters [default: all] -m, --partial-match Include cross-variant partial matches [default: full matches only] --reg-pop Filter to 'pop {reg} * 1+, {ret or ctrl-ed jmp/call}' gadgets [default: all] -r, --rop Search for ROP gadgets only [default: ROP, JOP, and SYSCALL] -p, --stack-pivot Filter to gadgets that write the stack ptr [default: all] -s, --sys Search for SYSCALL gadgets only [default: ROP, JOP, and SYSCALL] -V, --version Prints version information OPTIONS: -a, --arch <ARCH> For raw (no header) files: specify arch ('x8086', 'x86', or 'x64') [default: x64] -b, --bad-bytes <BYTE(S)>... Filter to gadgets whose addrs don't contain given bytes [default: all] -l, --max-len <LEN> Gadgets up to LEN instrs long. If 0: all gadgets, any length [default: 5] --no-deref <OPT_REG> Filter to gadgets that don't deref any regs or a specific reg [default: all] --reg-ctrl <OPT_REG> Filter to gadgets that control any reg or a specific reg [default: all] -f, --regex-filter <EXPR> Filter to gadgets matching a regular expression ARGS: <FILE(S)>... 1+ binaries to gadget search. If > 1: gadgets common to all
CLI Build and Install (Recommended)
Build a dynamically-linked binary from source and install it locally:
cargo install xgadget --features cli-bin # Build on host (pre-req: https://www.rust-lang.org/tools/install)
CLI Binary Releases for Linux
Commits to this repo's master
branch automatically run integration tests and build a statically-linked binary for 64-bit Linux.
You can download it here to try out the CLI immediately, instead of building from source.
Static binaries for Windows may also be supported in the future.
Unfortunately the statically-linked binary is several times slower on an i7-9700K, likely due to the built-in memory allocator for target x86_64-unknown-linux-musl
.
So building a dynamically-linked binary from source with the above cargo install
command is highly recommended for performance (links against your system's allocator).
Why No Chain Generation?
Tools that attempt to automate ROP chain generation require heavyweight analysis - typically symbolic execution of an intermediate representation.
While this works well for small binaries and CTF problems, it tends to be slow and difficult to scale for large, real-world programs.
At present, xgadget
has a different goal: enable an expert user to manually craft stable exploits by providing fast, accurate gadget discovery.
Yeah, but can it do 10 OS kernels under 10 seconds?! Repeatable Benchmark Harness
bash ./benches/bench_setup_ubuntu.sh # Ubuntu-specific, download/build 10 kernel versions
cargo bench # Grab a coffee, this'll take a while...
bench_setup_ubuntu.sh
downloads and builds 10 consecutive Linux kernels (versions5.0.1
to5.0.10
- withx86_64_defconfig
).cargo bench
, among other benchmarks, searches all 10 kernels for common gadgets.
On an i7-9700K (8C/8T, 3.6GHz base, 4.9 GHz max) machine with gcc
version 8.4.0: the average runtime, to process all ten 54MB kernels simultaneously with a max gadget length of 5 instructions and full-match search for all gadget types (ROP, JOP, and syscall gadgets), is only 6.3 seconds! Including partial matches as well takes just 7.9 seconds.
Acknowledgements
This project started as an optimized solution to Chapter 8, exercise 3 of "Practical Binary Analysis" by Dennis Andreisse [6], and builds on the design outlined therein.
References
Re-exports
pub use crate::binary::*; |
pub use crate::gadget::*; |
pub use crate::search::*; |
pub use crate::filters::*; |
pub use crate::semantics::*; |
Modules
binary | |
filters | |
gadget | |
search | |
semantics |