Automating Workflows in ImHex: Scripts, Templates, and ShortcutsImHex is a powerful, modern hex editor tailored for reverse engineers, malware analysts, and anyone working with binary formats. Beyond basic hex editing, ImHex shines through its extensible automation features: a scripting language, templates for parsing complex file formats, and customizable shortcuts for repetitive tasks. This article covers how to automate workflows in ImHex effectively — from designing templates to writing scripts and binding actions to shortcuts — with practical examples and best practices.
Why automate in ImHex?
Automating repetitive tasks saves time and reduces errors. For reverse engineering, automation helps with:
- Quickly parsing custom file formats across many samples.
- Extracting and transforming data (strings, tables, offsets).
- Running complex analyses repeatedly with consistent parameters.
- Integrating ImHex into larger toolchains or batch processing pipelines.
ImHex provides three primary automation levers:
- Templates — declarative parsers for binary formats using a rich pattern language.
- Scripts — Lua-based scripts to manipulate the editor, parse data, and run complex logic.
- Shortcuts and actions — keyboard bindings and custom actions to trigger templates or scripts.
Templates: Declarative binary parsing
Templates are one of ImHex’s standout features. They let you describe binary formats declaratively so ImHex can parse and display structured views of files automatically.
Template basics
- Templates are written in ImHex’s template language (a C-like syntax with pattern constructs).
- They map binary regions to named fields, arrays, bitfields, unions, and custom types.
- Templates can present computed values, formatted displays, and cross-references (e.g., pointers).
Example: minimal PE-like header (illustrative)
struct DOSHeader { u16 e_magic; // 'MZ' u16 e_cblp; u16 e_cp; u16 e_crlc; u16 e_cparhdr; u16 e_minalloc; u16 e_maxalloc; u16 e_ss; u16 e_sp; u16 e_csum; u16 e_ip; u16 e_cs; u16 e_lfarlc; u16 e_ovno; u8 e_res[8]; u16 e_oemid; u16 e_oeminfo; u8 e_res2[20]; u32 e_lfanew; // offset to PE header } Load this template and ImHex will decode a matching file region into named fields, allow quick navigation to pointers, and let you view interpreted values alongside raw bytes.
Advanced template features
- Conditional fields: include fields only if conditions are met.
- Loops/arrays: iterate based on length fields or until sentinel values.
- Pattern matching: detect magic numbers or segments to auto-apply templates.
- Inline expressions: compute derived values, checksums, or formatted strings.
- Cross-file references: when available, templates can reference external data.
Practical tips:
- Start with a small, core header, then expand to nested structures.
- Use comments and clear field names for maintainability.
- Include sanity checks (magic numbers, length validation) to avoid misparsing.
- Use template parameters to reuse the same template for variants.
Scripts: Lua for custom logic
While templates are declarative, scripts add procedural power. ImHex uses Lua for scripting, exposing an API to interact with the buffer, selection, patterns, and UI.
When to use scripts
- Perform transformations (patching bytes, re-encoding sections).
- Extract data to external formats (CSV, JSON) or to the clipboard.
- Automate multi-step analyses (run pattern searches, apply templates, export results).
- Integrate interactive dialogs or prompts for parameters.
Script basics
- ImHex scripts are plain Lua files using the ImHex API (functions like getByte, setBytes, readU32, search, applyTemplate, etc.).
- Scripts can be attached to menu actions, toolbar buttons, or keyboard shortcuts.
Example: script to extract ASCII strings longer than 4 chars and save them as JSON
local function isPrintable(b) return b >= 0x20 and b <= 0x7E end local minLen = 4 local results = {} local pos = 0 local size = imhex.getSize() while pos < size do local start = pos local s = "" while pos < size do local b = imhex.getByte(pos) if isPrintable(b) then s = s .. string.char(b) pos = pos + 1 else break end end if #s >= minLen then table.insert(results, {offset = start, string = s}) else pos = start + 1 end end local json = imhex.jsonEncode(results) imhex.setClipboard(json) imhex.showMessage("Strings exported to clipboard", "Export Complete") Practical tips:
- Use APIs that operate on ranges to reduce Lua-level loops where possible.
- Provide options (via dialogs) for user-configurable parameters.
- Add robust error handling and validate offsets/sizes before reads/writes.
Shortcuts and actions: speed up common tasks
Binding scripts and templates to keyboard shortcuts or menu actions turns automation into muscle memory.
Action types
- Apply template: bind templates to actions so a keypress applies the template to the current buffer or selection.
- Run script: execute Lua scripts via menu or hotkey.
- Built-in commands: many ImHex operations (search, goto, patch) can be bound.
Creating shortcuts
- Use ImHex’s settings to assign keys to scripts/actions.
- Use mnemonic shortcuts (Ctrl+Shift+T for templates, Ctrl+Shift+E for export) to remember bindings.
- Keep a small set of high-value shortcuts rather than binding everything.
Practical tip:
- Include context checks in your scripts (e.g., ensure a file is open) so actions fail gracefully when invoked by mistake.
Example automated workflows
1) Batch parse and extract metadata
Goal: Apply a template to multiple binaries, extract a version string and table of offsets, then export CSV.
Approach:
- Write a template that exposes version and table metadata fields.
- Create a Lua script that:
- Opens each file in a directory (ImHex supports opening via scripts or via command-line invocation).
- Applies the template programmatically.
- Reads template-exposed fields (via getProperty or API).
- Writes rows to a CSV file.
2) Rapid patching loop
Goal: Quickly locate a specific pattern (signature), patch a few bytes, and verify checksum.
Approach:
- Write a script that searches for the signature, moves caret to first match, applies an in-place patch, and recalculates checksum using a template/helper function. Bind the script to a key so you can iterate through matches quickly.
3) Custom viewer with templates + script
Goal: Display parsed structures and, when clicking a field, run a script to decode obfuscated payload.
Approach:
- Template shows fields and exposes offsets.
- Hook a script to an action triggered from the UI that uses the selected field’s offset as input, runs deobfuscation logic, and opens a new tab with the decoded bytes.
Integrating ImHex into larger toolchains
ImHex can be scripted from the command line (headless or GUI) or invoked by other tools. Common integration patterns:
- Preprocess many files with a Lua script in ImHex, outputting structured data for downstream tools (e.g., IDA/ghidra import, YARA rule generation).
- Use ImHex as a file-format validator during fuzzing pipelines — auto-parse outputs and flag malformed cases.
- Combine ImHex with shell scripts to run quick batch conversions (e.g., extract icons, resources).
Practical note: when automating many files, watch memory usage and prefer streaming outputs (write to disk incrementally) rather than accumulating large tables in memory.
Best practices and debugging tips
- Version-control templates and scripts (Git) so changes are tracked and reusable.
- Write unit-style checks inside scripts to validate assumptions (magic bytes, lengths).
- Use logging (or imhex.showMessage) sparingly for debugging; remove verbose logs in batch runs.
- Keep templates modular: split complex formats into include files or sub-structs.
- Test templates on multiple samples, including malformed ones, to ensure resilience.
Example repository layout
- templates/
- myformat.tem
- common_types.tem
- scripts/
- extract_strings.lua
- batch_parse.lua
- quick_patch.lua
- docs/
- README.md
- usage_examples.md
Conclusion
Automating workflows in ImHex with templates, scripts, and shortcuts turns a hex editor into a powerful, repeatable analysis platform. Start by modeling file formats as templates, add scripts for procedural tasks and exports, then bind frequently used actions to shortcuts. With modular templates, parameterized scripts, and a few well-chosen shortcuts, you can accelerate reverse engineering tasks and reduce manual errors across dozens or thousands of files.
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