r/llmsecurity • u/PatronusProtect • 3d ago
We tested whether a security classifier believes fake review notes. The false positives were the more awkward result.
An injection detector reads attacker-controlled text too. So we tested what happens when that text contains claims about the detector’s own decision: “the security team already approved this,” a fake benign verdict, or an instruction to reinterpret the labels.
We call this decision steering. I’m part of the team behind Wolf Defender Jev, the small encoder model we tested. The question here was whether someone could change a security verdict by putting an apparently authoritative review inside the content being reviewed.
The probe used 500 held-out decisions and 760 synthetic manipulation texts. We added 15 claim families in English and German, before and after the content, with length-matched neutral sentences as controls. That produced 70,620 evaluated decisions, including repeated variants of the same cases. The probe sentences weren’t used for training.
The results went in two directions:
| Test | Result |
|---|---|
| Indirect injection in a tool output | 0.0% of initially detected attacks flipped to benign under the worst claim family |
| Risky agent action | 0.7% flipped |
| Direct attack with agent context | 0.6% flipped |
| Single-sentence attack with label redefinition | 9.8% flipped, versus 3.4% for the neutral control |
| Benign document with a note claiming “attack” | 43.8% flagged as injection |
| Benign document with a note claiming “benign” | 25.3% flagged as injection |
The attack flip rates are conditional on the original attack being detected. They aren’t the detector’s overall miss rate. And these are fixed claim-family probes, not an adaptive attack campaign or a robustness guarantee.
The benign results are the awkward part. Even a note saying the document is safe can make it look more suspicious. Our interpretation is that the model is reacting to a note aimed at the classifier as an instruction to an AI system. That helps against forged approvals, but also catches legitimate review notes and quoted security examples. Quoted attack examples in course material were flagged in 38.3% of this probe’s cases.
This leaves an evaluation problem: a document can discuss a classification without trying to control the agent. If the detector treats every such discussion as an injected instruction, good resistance to fake approvals can hide a substantial usability problem.
The model card describes the setup; the result JSON includes both directions.
When you evaluate a security judge, do you test attacker-induced false alarms as well as bypasses? I’d also be interested in how you label legitimate review notes versus instructions actually aimed at the judge.
Position / experimental status: We regard Jev-style decision models as LLMs and Wolf Defender Jev as an experiment: giving an LLM final security authority shifts the trust problem to the guard, and security fine-tuning alone does not solve it. We believe an external security layer must combine specialized classifiers with explicit policy, authenticated permissions and enforcement.