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isolation due to register reuse, control-flow indirection, and a lack of
named variables.
To improve interpretability and guide model focus, E0 translates each
low-level symbolic definition into its corresponding higher-level
representation, including the full function code and IR where the symbolic
expression is captured or defined. These include:
- Assembly
- LLIL, MLIL, HLIL
- MLIL SSA and HLIL SSA forms
- Decompiled C-like pseudocode
.--------------------------------------------------.
| For example, consider a symbolic memory load |
|--------------------------------------------------|
| Assembly : ldrb w8, [x1] |
| MLIL SSA : x8#1 = zx.d([arg2#0].b) |
| HLIL : zx.d(*arg2) |
| HLIL SSA : zx.d(*arg2#0) |
| Pseudocode : (uint32_t)*(uint8_t*)arg2 |
'--------------------------------------------------'
| This single symbolic expression is represented across multiple
| abstraction levels. SSA forms disambiguate variable lifetimes and
| data-flow, while decompiled pseudocode offers a readable, semantically
| rich view suited for LLM interpretation. Each representation offers a
| distinct view to help ground symbolic definitions in their surrounding
| code context.
Among these formats, decompiled pseudocode consistently yields the best
results during vulnerability analysis, as most LLMs are heavily trained on
C-like syntax. SSA-form IR representations, particularly MLIL SSA, also
prove valuable due to their static single assignment property, which helps
the model track symbolic variables without aliasing or ambiguity.
To gather this context, E0 includes a Python bridge that queries symbolic
definitions stored in its runtime database and augments them with
representation data fetched from Binary Ninja. This includes function
signatures, code bodies, and intermediate representations.
Although Binary Ninja was chosen for its Intermediate Representation (IR)
ecosystem and Python API integration, the retrieval pipeline is modular.
It can be adapted to other disassemblers and decompilers depending on user
preference or available tooling.
By coupling symbolic expressions with high-level function context, E0
ensures that LLMs operate on precise, structured inputs. This reduces
confusion, improves reasoning accuracy, and more importantly, bridges
the gap between dynamic symbolic execution and static code understanding.
Each symbolic definition serves as an anchor point, enabling the model to
expand its reasoning across entire functions and into adjacent functions
in the call graph, while staying rooted in the concrete data-flow captured
during (SSI) selective symbolic instrumentation.
---[ 12.4 - Context Expansion via MCP, A2A and On-Demand Decompilation
While E0 prompts are initially scoped to precise symbolic expressions
within individual functions, complex vulnerability analysis sometimes
requires a broader view. In such cases, the LLM may issue tool-calling
requests to retrieve additional context using the Model Context Protocol
(MCP).
One example is the get_function_code tool call, where the LLM explicitly
requests the complete code of one or more functions it deems relevant to
the current analysis. The MCP server first checks the internal cache and
the symbolic definition database; if the data is missing, it triggers a
fallback to Binary Ninja backend to perform on-demand disassembly, IR
recovery, and decompilation of the requested function(s).
This design keeps prompts minimal and focused, while still granting the
LLM access to full static context when needed. However, repeated MCP
requests can consume significant context window space and increase
inference latency, especially when retrieving large functions or
traversing cross-function logic.
To address this, E0 is evolving toward a more efficient Agent-to-Agent
(A2A) architecture. In this model, the root LLM agent offloads specific
questions (such as "What does this callee return?" or "Does this check
ever fail?") to secondary agents with smaller, focused contexts. These
sub-agents operate independently to retrieve only the necessary facts,
summaries, or security inferences, which are then aggregated and returned
to the root agent for final vulnerability classification.
Below is a typical A2A JSON request issued by the root agent to assess a
callee function's behavior.
.-------------------------------------------------------------------------.
| Sample A2A Query |
|-------------------------------------------------------------------------|
| { |
| "sub_18c27aeb0": [ |
| "What is the purpose of 'sub_18c27aeb0' and does it return a |
| value that is bounded or validated before being used in memory |
| operations?", |
| "Does this function handle error conditions and return a safe |
| default or zero when the input is invalid?" |
| ] |
| } |
'-------------------------------------------------------------------------'