{"data":{"id":"54f890bc-19f0-435a-b29f-124c29704a64","title":"Rewriting less than 10 neurons in an LLM can turn it into a sleeper backdoor","summary":"Microsoft Research describes Lazarus, a technique that rewrites fewer than 10 dormant neurons in an open-weight model's final feed-forward layer so the model emits attacker-chosen commands when a trigger appears, with no retraining. Tested on Nvidia's Nemotron-Terminal-8B by modifying seven of more than 12,000 neurons, the backdoor fired in at least 98.8% of held-out trigger scenarios and stayed inactive on benign inputs. The attack requires write access to the model checkpoint.","solution":"In its accompanying security advisory, Microsoft Threat Intelligence recommends auditing model weights bef","labels":["security","research"],"sourceUrl":"https://www.csoonline.com/article/4247354/rewriting-less-than-10-neurons-in-an-llm-can-turn-it-into-a-sleeper-backdoor.html","publishedAt":"2026-11-11T12:28:03.000Z","cveId":null,"cweIds":null,"cvssScore":null,"cvssSeverity":null,"severity":"medium","attackType":["model_poisoning","supply_chain"],"issueType":"news","affectedPackages":null,"affectedPackageNames":null,"affectedPackageRefs":null,"affectedVendors":["Microsoft","NVIDIA","Google"],"affectedVendorsRaw":["Nemotron-Terminal-8B","Qwen 3.6-27B","Gemma-4-31B-IT"],"classifierModel":"claude-haiku-5-5","classifierPromptVersion":"v4","summaryPromptVersion":"v2","headline":null,"headlinePromptVersion":null,"cvssVector":null,"attackVector":null,"attackComplexity":null,"privilegesRequired":null,"userInteraction":null,"exploitMaturity":null,"epssScore":null,"epssCheckedAt":null,"kevDateAdded":null,"advisoryAliases":null,"affectedPackagesSource":null,"affectedPackagesCheckedAt":null,"patchAvailable":null,"disclosureDate":"2026-11-11T12:28:03.000Z","fixReleasedAt":null,"daysToFix":null,"fixCheckedAt":null,"capecIds":null,"crossRefCount":0,"attackSophistication":"advanced","impactType":["integrity","confidentiality","availability"],"aiComponentTargeted":"model","llmSpecific":true,"classifierConfidence":0.9,"researchCategory":null,"atlasIds":["AML.T0010"]}}