# Detecting Voice Phishing with Precision: Fine-Tuning Small Language Models

arXiv: https://arxiv.org/abs/2506.06180 · HTML: https://mlsanity.com/paper/2506.06180/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- Builds on 10 of its 24 references that are in the map.
- First posted on arXiv 6 Jun 2025.

## Builds on (most cited first, 10 of 10)

- [The Llama 3 Herd of Models](https://mlsanity.com/paper/2407.21783/) (2024)
- [LoRA: Low-Rank Adaptation of Large Language Models](https://mlsanity.com/paper/2106.09685/) (2021)
- [Llama 2: Open Foundation and Fine-Tuned Chat Models](https://mlsanity.com/paper/2307.09288/) (2023)
- [Chain-of-Thought Prompting Elicits Reasoning in Large Language Models](https://mlsanity.com/paper/2201.11903/) (2022)
- [Large Language Models Are Reasoning Teachers](https://mlsanity.com/paper/2212.10071/) (2022)
- [Teaching Small Language Models to Reason](https://mlsanity.com/paper/2212.08410/) (2022)
- [Accessing GPT-4 level Mathematical Olympiad Solutions via Monte Carlo Tree Self-refine with LLaMa-3 8B](https://mlsanity.com/paper/2406.07394/) (2024)
- [A Comprehensive Survey of Small Language Models in the Era of Large Language Models: Techniques, Enhancements, Applications, Collaboration with LLMs, and Trustworthiness](https://mlsanity.com/paper/2411.03350/) (2024)
- [AD-LLM: Benchmarking Large Language Models for Anomaly Detection](https://mlsanity.com/paper/2412.11142/) (2024)
- [Optimizing Language Augmentation for Multilingual Large Language Models: A Case Study on Korean](https://mlsanity.com/paper/2403.10882/) (2024)

## Built on by (most cited first, 2 of 2)

- [Anatomy of a Scam Call: What 10,000 real scam and spam calls reveal about how phone scammers operate](https://mlsanity.com/paper/2608.24127/) (2026)
- [Comparing Self-Supervised and Domain-Invariant Features for Cross-Domain Voice Phishing Detection](https://mlsanity.com/paper/2609.07079/) (2026)

## Abstract (arXiv)

We develop a voice phishing (VP) detector by fine-tuning Llama3, a representative open-source, small language model (LM). In the prompt, we provide carefully-designed VP evaluation criteria and apply the Chain-of-Thought (CoT) technique. To evaluate the robustness of LMs and highlight differences in their performance, we construct an adversarial test dataset that places the models under challenging conditions. Moreover, to address the lack of VP transcripts, we create transcripts by referencing existing or new types of VP techniques. We compare cases where evaluation criteria are included, the CoT technique is applied, or both are used together. In the experiment, our results show that the Llama3-8B model, fine-tuned with a dataset that includes a prompt with VP evaluation criteria, yields the best performance among small LMs and is comparable to that of a GPT-4-based VP detector. These findings indicate that incorporating human expert knowledge into the prompt is more effective than using the CoT technique for small LMs in VP detection.