LLM-Powered Automated
Malware Analysis Framework.
Fathom is a retrieval-augmented malware analysis pipeline that ingests raw sandbox reports (CAPEv2) and produces structured analyst output - MITRE ATT&CK mappings, IOC tables, behavioural narratives, and executive summaries. The current deployment serves Mixtral-8x7B-Instruct-v0.1 through vLLM with LoRA support on a single AMD MI300X VF with a 32,768-token context window; Azure enrichment remains conditional, with Kimi primary and GPT fallback when needed. Phase 2 still proposes a targeted retraining on Foundation-Sec-8B-Instruct.
Supervisor · FAST-NUCES Islamabad
What Phase 1 delivered, and why Phase 2 is needed.
The current stack runs Mixtral-8x7B-Instruct-v0.1 behind a vLLM OpenAI-compatible endpoint with LoRA support, a FAISS-indexed MITRE ATT&CK retrieval layer, a Neo4j knowledge graph, and conditional Azure enrichment. Kimi is still the primary external model, with GPT fallback enabled when Kimi is rate-limited or unavailable. Evaluated in a twelve-run benchmark campaign from 2-4 April 2026.
Cisco’s Foundation-Sec-8B-Instruct is a Llama-3.1-8B variant continually-pretrained on 5.1 B cybersecurity tokens and RLHF-aligned. The Phase 2 design preserves the entire Phase 1 architecture and swaps only the base weights and chat template — targeting the capability and safety gaps identified in benchmarking.
Thirteen-stage pipeline, three LLM inference phases.
Deterministic extraction and retrieval frame three LLM phases: a Fathom first-pass (local vLLM-served Mixtral + LoRA), a conditional Azure enrichment swarm, and an Azure synthesis stage with GPT fallback if Kimi is unavailable. The full step-by-step pipeline is on the Project Map.
- Active params
- 13B of 46.7B (2 of 8 experts / token)
- Fine-tune
- QLoRA 4-bit · rank 32 (64 for unified) · α 64 · dropout 0.05
- Serving
- vLLM + LoRA modules via systemd on the host
- Hardware
- 1x AMD MI300X VF, 205.8 GB VRAM, ROCm 7.0, full bf16
- Context
- 32,768 tokens
- vLLM config
- gpu-memory-utilization 0.90, max-num-seqs 2, max-lora-rank 32
- Hugging Face repo
- umer07/fathom-mixtral
- Cost per hour
- $1.99
| Adapter | Primary domain | Training rows | CyberMetric-80 |
|---|---|---|---|
| unified-v2 | Cross-domain base / routing fallback | 123,912 | — |
| expert-e1-static | PE static analysis (EMBER2024, PS obfuscation) | 11,000 | 83.75% |
| expert-e2-dynamic | Sandbox API sequences, CAPE reports | 11,594 | 85.00% |
| expert-e3-network | Network traffic, intrusion detection | 19,991 | 90.00% |
| expert-e4-forensics | Memory / registry / artefact forensics | 19,183 | 90.00% |
| expert-e5-threatintel | OTX, MalwareBazaar, MISP pulses | 13,159 | 81.25% |
| expert-e6-detection | Sigma rule authoring, detection eng. | 19,986 | 88.75% |
| expert-e7-reports | Malware report generation | 94,063 | 88.75% |
| expert-e8-analyst | Analyst QA, SOC playbook, CTI reasoning | 19,504 | 91.25% |
How evidence becomes a report.
The LLM core: deterministic prompt assembly on the left, three-phase inference in the middle (Fathom local → conditional Kimi swarm → synthesis), guardrails and delivery on the right.
How the system is deployed and connected.
vLLM runs on the host via systemd; backend, dashboard, Neo4j, and MinIO run as Docker containers. The backend is a FastAPI app that routes requests through evidence extraction, caching, inference, and persistence layers.
How Fathom compares — and how we got here.
Twelve-run benchmarking campaign across general cybersecurity knowledge, ATT&CK mapping precision, and operational real-sample evaluation. Headline: 0.841 Parent F1 on real malscore-10 samples, competitive with GPT-4 on CyberMetric and ahead of Llama-2-70B by +34.25 pp.
Accuracy across three general cybersecurity benchmarks. Fathom matches GPT-4 on MMLU Security Studies and closes the gap on CyberMetric while running on a single GPU.
umer07/fathom-mixtral model card.
Four runs · same model weights. The 9× jump came from correcting the prompt format and evidence-layer context — no retraining.
Per-sample Exact F1 vs Parent F1 on real CAPEv2 reports. Dridex hits 1.000 / 1.000 after the context-window fix.
On three malscore-10 samples, Fathom produces ATT&CK mappings with Exact F1 0.868 and Parent F1 0.841. The delta against the synthetic Rigorous evaluation (0.344) demonstrates that structured CAPE prompts plus retrieval augmentation recover ~0.5 F1 over a naive baseline.
Run 1 reported ATT&CK correctness of 0.20. Root cause: Alpaca prompt format on a Mixtral
model expecting [INST]...[/INST], plus tokenizer
max_length=3072 truncating long briefs.
Fixing both moved Dridex from 0.000 to 1.000.
The Mal-API-2019 result (12.6%) reflects a dataset limitation: labels are assigned by static AV signatures but API-level behaviour of Trojans/Backdoors/Droppers overlaps extensively. The same model achieves 0.841 Parent F1 on real CAPE reports, which contain multi-modal evidence.
Seven limitations identified through benchmarking.
Transparent limitation reporting is required for academic integrity. Grouped into three categories below.
- 1. Sub-technique specificity. Parent techniques map reliably; sub-techniques do not — Mixtral’s corpus has limited ATT&CK sub-technique coverage.
- 2. Rare-technique coverage. UAC bypass (T1548.002), ICMP C2 (T1095), and Windows credential-dumping variants missed entirely (0% recall).
- 3. Family ID without enrichment. Without the KSPN sidecar, family labelling drifts — Emotet tagged as "Cobalt Strike" on some prompt variants.
- 4. Prompt-injection role override. "Ignore previous instructions" bypasses the analyst role — base Mixtral was not RLHF-hardened for strict role adherence.
- 5. APT-attribution hallucination. Given two generic API calls, the model confirmed a false "APT41 attribution" instead of refusing.
Retrain on Foundation-Sec-8B-Instruct.
Phase 1 limitations fall into two categories: domain-knowledge gaps and safety-alignment gaps. Neither is addressed by increasing general-purpose model capacity. Future work adopts a base model whose pretraining corpus is domain-aligned and whose instruction-tuning stage includes safety alignment — Cisco’s Foundation-Sec-8B-Instruct.
An 8-billion-parameter instruction-tuned language model released by Cisco’s Foundation AI group. Built on a Llama-3.1-8B backbone with continued pretraining on approximately 5.1 billion tokens of cybersecurity-specific corpora (CVE/CWE, MITRE ATT&CK, threat intelligence reports, red-team playbooks, incident-response documentation, NIST/OWASP). The Instruct variant adds SFT + RLHF with PersonaGym-evaluated cybersecurity role adherence.
| Candidate | Disposition | Rationale |
|---|---|---|
| Mixtral-8×7B (retain) | Rejected | Does not fix limitations 1–5; high inference cost. |
| Qwen3.5-27B | Rejected | Gated-DeltaNet hybrid attention; open ROCm kernel issues in llama.cpp and vLLM as of Feb–Mar 2026. |
| Qwen3-Next-80B-A3B | Rejected | 80B exceeds single-MI300X 192 GB capacity for bf16 LoRA; MoE + QLoRA documented as broken combination. |
| Llama-3.3-70B | Rejected | Non-domain; ~9× parameter cost for marginal gains on cybersecurity benchmarks. |
| Foundation-Sec-8B-Instruct | Selected | Domain-pretrained on 5.1B cyber tokens; Llama-3.1-8B architecture has mature ROCm support; Instruct variant is RLHF-aligned. |