rhabdomancer

"The road to exploitable bugs is paved with unexploitable bugs."

-- Mark Dowd

Rhabdomancer is a blazing fast IDA Pro headless plugin that locates calls to potentially insecure API functions in a binary file. Auditors can backtrace from these candidate points to find pathways allowing access to untrusted input.

Features

• Blazing fast, headless user experience courtesy of IDA Pro 9.x and Binarly's idalib Rust bindings.
• Support for C/C++ binary targets compiled for any architecture implemented by IDA Pro.
• Bad API function call locations are printed to stdout and marked in the IDB.
• Known bad API functions are grouped in tiers of badness to help prioritize the audit work.
  • [BAD 0] High priority - Functions that are generally considered insecure.
  • [BAD 1] Medium priority - Interesting functions that should be checked for insecure use cases.
  • [BAD 2] Low priority - Code paths involving these functions should be carefully checked.
• The list of known bad API functions can be easily customized by editing conf/rhabdomancer.toml.

Blog posts

• https://hex-rays.com/blog/streamlining-vulnerability-research-idalib-rust-bindings
• https://hnsecurity.it/blog/streamlining-vulnerability-research-with-ida-pro-and-rust

See also

• https://github.com/0xdea/ghidra-scripts/blob/main/Rhabdomancer.java
• https://docs.hex-rays.com/release-notes/9_0#headless-processing-with-idalib
• https://github.com/idalib-rs/idalib
• https://books.google.it/books/about/The_Art_of_Software_Security_Assessment.html

Installing

The easiest way to get the latest release is via crates.io:

1. Download, install, and configure IDA Pro (see https://hex-rays.com/ida-pro).
2. Install LLVM/Clang (see https://rust-lang.github.io/rust-bindgen/requirements.html).
3. On Linux/macOS, install as follows:

   export IDADIR=/path/to/ida # if not set, the build script will check common locations
   cargo install rhabdomancer

   On Windows, instead, use the following commands:

   $env:LIBCLANG_PATH="\path\to\clang+llvm\bin"
   $env:PATH="\path\to\ida;$env:PATH"
   $env:IDADIR="\path\to\ida" # if not set, the build script will check common locations
   cargo install rhabdomancer

Compiling

Alternatively, you can build from source:

1. Download, install, and configure IDA Pro (see https://hex-rays.com/ida-pro).
2. Install LLVM/Clang (see https://rust-lang.github.io/rust-bindgen/requirements.html).
3. On Linux/macOS, compile as follows:

   git clone --depth 1 https://github.com/0xdea/rhabdomancer
   cd rhabdomancer
   export IDADIR=/path/to/ida # if not set, the build script will check common locations
   cargo build --release

   On Windows, instead, use the following commands:

   git clone --depth 1 https://github.com/0xdea/rhabdomancer
   cd rhabdomancer
   $env:LIBCLANG_PATH="\path\to\clang+llvm\bin"
   $env:PATH="\path\to\ida;$env:PATH"
   $env:IDADIR="\path\to\ida" # if not set, the build script will check common locations
   cargo build --release

Usage

1. Make sure IDA Pro is properly configured with a valid license.
2. Customize the list of known bad API functions in conf/rhabdomancer.toml if needed. You can override the default configuration file location by setting the RHABDOMANCER_CONFIG environment variable.
3. Run as follows:

   rhabdomancer <binary_file>

   Any existing .i64 IDB file will be updated; otherwise, a new IDB file will be created.
4. Open the resulting .i64 IDB file with IDA Pro.
5. Select View > Open subviews > Bookmarks
6. Enjoy your results conveniently collected into an IDA Pro window.

Note

Rhabdomancer also adds comments at marked call locations.

Compatibility

Only the latest IDA Pro release is officially supported, but older versions may work as well. The following table summarizes the latest compatible release for each IDA Pro version:

IDA Pro version	Latest compatible release
v9.0.240925	v0.2.4
v9.0.241217	v0.3.5
v9.1.250226	v0.6.2
v9.2.250908	v0.7.6
v9.3.260213	v0.8.1
v9.3.260327	v0.9.0
v9.3.260421	current release

Note

Check the idalib documentation for additional information.

Changelog

• CHANGELOG.md

TODO

• Enrich the known bad API function list (see https://github.com/0xdea/semgrep-rules).
• Consider converting traverse_xrefs to an iterative walk to avoid potential stack overflows and infinite loops.
• Consider broadening the scope of normalization in normalize_name to account for more cases.
• Implement a basic ruleset in the style of VulFi and VulnFanatic.