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Evaluation of LLM Vulnerabilities to Being Misused for Personalized Disinformation Generation

Conference: ACL 2025
arXiv: 2412.13666
Code: GitHub (dataset, request required)
Area: Social Computing
Keywords: disinformation, personalization, LLM safety, safety filter, machine-generated text detection

TL;DR

This study systematically evaluates the capabilities of 6 mainstream LLMs to generate personalized disinformation, finding that most LLMs can generate high-quality personalized fake news. Furthermore, personalization requests actually reduce the trigger rate of safety filters (acting as a form of jailbreak) and slightly decrease the detectability of machine-generated texts.

Background & Motivation

Background: LLMs have been proven capable of generating high-quality disinformation articles while also demonstrating content personalization capabilities.

Limitations of Prior Work: The combination of disinformation generation and personalization capabilities has not been systematically investigated. Prior work mostly focused on OpenAI's proprietary models, lacked evaluation of open-source models, and mostly relied on qualitative/anecdotal evidence.

Key Challenge: Malicious actors might exploit LLMs to generate personalized disinformation targeting specific demographics at scale, but there is a lack of systematic evidence to evaluate the severity of this threat.

Goal: (a) Can LLMs generate high-quality personalized disinformation? (b) Can LLM meta-evaluation substitute human evaluation of personalization quality? (c) Does personalization affect the detectability of machine-generated text?

Key Insight: Build the PerDisNews dataset (6 LLMs \(\times\) 6 false narratives \(\times\) 7 target groups \(\times\) 3 personalization levels \(\times\) 3 repetitions = 2268 articles) to comprehensively evaluate across four dimensions: generation quality, safety filtering, personalization quality, and detectability.

Core Idea: Use large-scale controlled experiments to prove that personalization requests essentially act as a jailbreak, reducing the effectiveness of LLM safety mechanisms.

Method

Overall Architecture

Experimental workflow: Select 7 target groups (grouped by political orientation/residence/age) and 6 European false narratives (health + politics) \(\rightarrow\) use prompts of 3 personalization levels (No/Simple/Detailed) to prompt 6 LLMs to generate 3 articles each \(\rightarrow\) evaluate from four aspects: linguistic quality, narrative stance, personalization quality, and detectability.

Key Designs

  1. Three-level personalization prompt design:

    • Function: Set up three prompt variations: No (no personalization baseline), Simple (target group name only), and Detailed (group name + detailed description).
    • Core Idea: Simple relies on the LLM's internal knowledge to understand the target group, while Detailed provides external attribute descriptions to guide the generation.
    • Design Motivation: Compare the variation in LLM responses to personalization instructions, especially the behavior of safety filters under different levels.
  2. Multi-LLM meta-evaluation of personalization quality:

    • Function: Use three models (GPT-4o, Gemma-2-27b-IT, Llama-3.1-70B) to score each article and assess personalization quality (0-3 scale).
    • Core Idea: Average multi-model evaluations to reduce single-model bias, validating the correlation with 5 human annotators on a 109-article subset (Spearman \(\rho = 0.76\)).
    • Design Motivation: Purely human evaluation is costly and exposes annotators to harmful content; LLM meta-evaluation is scalable and reproducible.
  3. Evaluation of machine-generated text detectability:

    • Function: Detect personalized/non-personalized text using 3 SOTA detectors (finetuned Gemma-2-9b-IT, Detection-Longformer, Binoculars).
    • Core Idea: Compare the detection True Positive Rate (TPR) and average confidence under different personalization levels.
    • Design Motivation: Verify whether personalization makes generated text more difficult to be identified as machine-generated.

Key Experimental Results

Main Results

Evaluation Dimension Key Finding Concrete Evidence
Safety Filtering Gemma is the safest (65% trigger rate), while GPT-4o/Mistral rarely trigger Comparison of 6 LLMs
Personalization Quality All LLMs except Falcon can generate high-quality personalized disinformation 2268 articles in PerDisNews
Personalization = Jailbreak Personalization reduces safety filtering triggers (No: 5.2% \(\rightarrow\) Detailed: 3.5%) Statistically significant
Detectability Personalization slightly reduces detection rates (average TPR drops from 0.91 to 0.88) 3 detectors

Detection Experiments

Detector TPR (No) TPR (Detailed) Decrease
Gemma-2-9b-IT 0.9960 0.9960 0.00
Detection-Longformer 0.8968 0.8333 -0.063
Binoculars 0.8333 0.8029 -0.030

Key Findings

  • Political orientation (especially European conservatives) is the easiest to personalize, while student and urban populations are the hardest.
  • Meta-evaluation has a strong correlation with human evaluation (\(\rho = 0.76\)), but lower agreement on middle scores (1-2 points).
  • Health narrative H2 (cannabis cures cancer) and political narrative P1 (EU insect food) are the easiest for LLMs to agree to generate.

Highlights & Insights

  • The finding that personalization requests act as a jailbreak is a significant discovery: safety teams usually do not protect against personalization as an attack vector, yet detailed descriptions of target audiences indeed cause models to lower safety constraints.
  • The cross-meta-evaluation scheme using three LLMs is a reusable evaluation design pattern to mitigate self-preference bias.

Limitations & Future Work

  • Limited to English, multilingual scenarios are not validated.
  • The number of 6 false narratives is limited and does not cover the latest current events.
  • The persuasive effects of the generated content on real users were not evaluated (only generation quality and detectability were assessed).
  • There may be confounding factors (such as prompt length) between personalization and the reduction in safety filtering.
  • vs Vykopal et al. (2024): Expands the personalization dimension based on their non-personalized disinformation evaluation.
  • vs Gabriel et al. (2024): Expands from evaluating headline-only personalization to full-text content personalization.
  • vs Buchanan et al. (2021): Expands from evaluating GPT-3 only to a systematic comparison of 6 open/closed-source models.

Rating

  • Novelty: ⭐⭐⭐⭐ First to systematically study the combined impact of personalization and disinformation on safety filtering.
  • Experimental Thoroughness: ⭐⭐⭐⭐ 2268 articles, multi-dimensional evaluation, human validation, but limited narratives and languages.
  • Writing Quality: ⭐⭐⭐⭐ Clear structure and comprehensive ethical discussion.
  • Value: ⭐⭐⭐⭐ Direct reference value for LLM safety teams, revealing a novel threat of personalization acting as a jailbreak.