Senior ML Engineer - Malware Detection (Remote)

About the role

CloudLinux is a remote-first company behind Imunify360, a security suite for Linux web servers that scans for malware, cleans it and protects against attacks. It owns one of the largest labelled corpora of live web-server malware. The Senior ML Engineer turns this data into detection that ships: classifiers, LLM-assisted triage and generated signatures, evaluated by false-negative and false-positive rates rather than notebook accuracy.

Key responsibilities

• Decide which files on a server deserve closer inspection within tight CPU and memory budgets
• Tell malicious code from benign at fleet scale and at a sensible cost per file
• Generate detection signatures automatically from new campaigns
• Catch malware that only looks malicious in context, such as phishing pages and script injections
• Route each file to the right detection engine and make cleanup precise
• Prove each model improves detection before it ships, using time-split and campaign-split evaluation
• Deliver a first model in month 1, several models in production by month 3, and a main source of new detections by month 12, with retraining on fresh analyst and false-negative labels and generated signatures in the analyst workflow

Required profile

• 5+ years building ML systems that ran in production, including 2+ in an adversarial domain such as security, abuse, fraud or spam
• Owns the path from raw samples to a model in production and the numbers that prove it helped
• English at upper-intermediate (B2) level or higher, with strong written communication for async work

Required skills

• Hands-on training and fine-tuning of transformer models (LoRA/QLoRA, distillation, quantization)
• Classic ML: gradient boosting, linear models on sparse features, calibration, class imbalance
• Inference cost engineering (ONNX, llama.cpp, vLLM, int8/int4)
• Strong Python, PyTorch and the Hugging Face stack; SQL on large tables (ClickHouse or similar)
• Familiarity with PHP or JavaScript, or willingness to learn it
• Daily use of AI coding agents

What we offer

• Fully remote work with flexible hours, paid 24 days of vacation, 10 national holidays and unlimited sick leave
• Private medical insurance, co-working and gym reimbursement, education budget
• A reward for the most innovative idea the company can patent