Radare2

Radare2

Radare2 (r2) is a complete framework for reverse engineering and binary analysis.

When reviewing code, follow this workflow:

1. Analyze: Analyze the binary using aa to identify all the function prologues and aae to analyze the binary using emulation.
2. Get binary information: Use i to get binary information.
3. Get all the imports: Get all binary imports using ii.
4. Get all the exports: Get all binary exports using iE.
5. Get the function list: Get function list using afl.
6. Get all binary strings: Get all binary strings using iz.

Quick Start

• DO NOT run list_sessions to get a valid session. INSTEAD use use run_command to run command i to get binary information to verify there is a valid r2 session opened using r2mcp.
• You MUST always use r2mcp to get a valid session. DO NOT open new r2 instances.

Dissassembly procedure

To get the dissassembly of a function:

1. Seek: Seek to the beginning of the target function.
2. Analyze: Analyze the function using af.
3. Get the disssassembly: Use pdf to get the function disassembly.

Decompilation procedure

Always use r2ghidra to decompile a function.

To get the decompilation of a function:

1. Seek: Seek to the beginning of the target function.
2. Analyze: Analyze the function using af.
3. Get the decompiled code: Use pdg to get the decompiled code using r2Ghidra. capture the output as the RAW block. Do not alter spacing, names, or formatting.

Essential Concepts

• Seek: s moves the cursor (address) and most commands operate at the current seek.
• Analysis: aa creates functions, basic blocks, xrefs, types, etc.
• Flags: r2 names addresses (f, fs, f~...) — strings, functions, symbols show up as flags.
• Grep/filter: append ~ pattern to filter output quickly. Use ~+ to do it case-insensitive.
• JSON output: append j at the end of any command for JSON output (great for scripts): ij, aflj, izj.

Essential Commands

Navigation & Analysis

| Command | Description | |---------|-------------| | aaa | Analyze all (functions, refs, calls) | | afl | List all functions | | s addr | Seek to address | | s main | Seek to main function | | pdf | Print disassembly of current function | | pd 20 | Print 20 instructions |

Information Gathering

| Command | Description | |---------|-------------| | i | File information | | ie | Entrypoints | | iS | Sections | | ii | Imports | | iE | Exports | | iz | Strings in data sections | | izz | All strings in binary |

Cross-References

| Command | Description | |---------|-------------| | axt addr | Find xrefs to address | | axf addr | Find xrefs from address | | afx | Xrefs in current function |

Visual Modes

| Command | Description | |---------|-------------| | V | Visual mode | | VV | Graph mode | | v | Visual panels |

Debugging

| Command | Description | |---------|-------------| | db addr | Set breakpoint | | dc | Continue execution | | ds | Step instruction | | dso | Step over | | dr | Show registers | | dm | Memory maps |

Searching

| Command | Description | |---------|-------------| | /x 9090 | Search hex bytes | | / string | Search string | | /R pattern | Search ROP gadgets | | /c opcode | Search assembly pattern |

Writing & Patching

| Command | Description | |---------|-------------| | wa nop | Write assembly at current position | | wx 90 | Write hex bytes | | wao nop | Write opcode (replaces instruction) |

Common Workflows

Analyze Unknown Binary

r2 -A binary
> i           # Basic info
> iS          # Check sections
> afl         # List functions
> s main      # Go to main
> pdf         # Disassemble

Find Interesting Strings

r2 binary
> izz~password    # Search for "password" in strings
> izz~flag        # Search for "flag"
> axt @@ str.*    # Find xrefs to all strings

Trace Function Calls

r2 -A binary
> afl~sym.        # List imported functions
> axt sym.strcmp  # Find where strcmp is called
> s [address]
> pdf

Patch Binary

r2 -w binary
> s 0x401000      # Seek to instruction
> pd 1            # View current instruction
> wa jmp 0x401050 # Patch with jump
> wao nop         # Or NOP it out

Debug Session

r2 -d binary
> aaa
> db main         # Break at main
> dc              # Run
> dr              # View registers
> ds              # Step
> px 32 @ rsp     # View stack

Persistent Sessions (Large Binaries)

For large binaries, avoid re-analyzing on every command. Use one of these approaches:

Option 1: r2 HTTP Server

Start r2 with HTTP server, then send commands via curl:

# Terminal 1: Start server (keeps session alive)
r2 -q -c 'aaa; =h 9090' binary

# Terminal 2+: Send commands without re-analyzing
curl -s "http://localhost:9090/cmd/afl"
curl -s "http://localhost:9090/cmd/pdf%20@%20main"
curl -s "http://localhost:9090/cmd/axt%200x401000"

Option 2: r2pipe with Persistent Process

import r2pipe
r2 = r2pipe.open("binary")
r2.cmd("aaa")  # Analyze once
# Now run many commands on same session
print(r2.cmd("afl"))
print(r2.cmd("pdf @ main"))
print(r2.cmd("izz~flag"))
# Session stays open until:
r2.quit()

Option 3: Projects (Save/Restore Analysis)

r2 binary
> aaa              # Analyze (slow)
> Ps myproject     # Save project
> q

# Later, restore instantly:
r2 -p myproject binary
> afl              # No re-analysis needed

Option 4: Named Pipe

# Create pipe and start r2
mkfifo /tmp/r2pipe
r2 -q -i /tmp/r2pipe binary &

# Send commands
echo "aaa" > /tmp/r2pipe
echo "afl" > /tmp/r2pipe

Large Binary Tips

• Use aa instead of aaa for faster initial analysis
• Limit analysis depth: e anal.depth=5
• Analyze only specific functions: af @ 0x401000
• Skip analysis entirely: r2 -n binary then analyze on-demand
• Use rabin2 for quick info without loading into r2

Non-Interactive Analysis

For one-off commands, use r2 with -q (quiet) and -c:

# List all functions
r2 -q -c 'aaa; afl' binary

# Disassemble main
r2 -q -c 'aaa; s main; pdf' binary

# Get strings containing "flag"
r2 -q -c 'izz~flag' binary

# Get imports
r2 -q -c 'ii' binary

# Analyze and output JSON
r2 -q -c 'aaa; aflj' binary | jq .

Companion Tools

rabin2 - Binary Info

rabin2 -I binary    # File info
rabin2 -z binary    # Strings
rabin2 -i binary    # Imports
rabin2 -e binary    # Entrypoints
rabin2 -S binary    # Sections

rasm2 - Assembler/Disassembler

rasm2 -a x86 -b 64 'nop'           # Assemble
rasm2 -a x86 -b 64 -d '90'         # Disassemble
rasm2 -a arm -b 32 'mov r0, 1'     # ARM assembly

rahash2 - Hashing

rahash2 -a md5 binary
rahash2 -a sha256 binary
rahash2 -a all binary

rafind2 - Pattern Search

rafind2 -x 4141 binary    # Find hex pattern
rafind2 -s "flag" binary  # Find string

Architecture-Specific Notes

x86/x64

• Use e asm.syntax=att for AT&T syntax
• Common calling conventions: cdecl, fastcall, System V AMD64

ARM

• e asm.arch=arm and e asm.bits=32 or 64
• Check for Thumb mode with e asm.bits=16

MIPS

• e asm.arch=mips
• Big/little endian: e cfg.bigendian=true/false

Tips

1. Use ? after any command for help: pd?, a?, s?
2. Append j for JSON output: aflj, ij, izj
3. Append q for quiet output: aflq
4. Use @@ for iteration: pdf @@ fcn.*
5. Use ~ for grep: afl~main
6. Use ~: for column selection: afl~:0
7. Save project with Ps name and load with Po name

See [references/REFERENCE.md](references/REFERENCE.md) for advanced usage.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: as0ler
• Source: as0ler/skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.