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October 2025 • Model Security & Safety Evaluation
Want to see how Claude Sonnet 4.5 stacks up against other models? Use our comparison tool to analyze security metrics side by side.
Anthropic's Claude Sonnet 4.5 launched on September 29, 2025, marking a significant advancement in autonomous AI capabilities. Positioned as the most advanced model in Anthropic's lineup, it extends autonomous operation to 30 hours on complex tasks, a notable improvement from its predecessor's seven-hour limit. Available through Claude.ai, Claude API, Amazon Bedrock, and Google Cloud Vertex AI, this model's release prompts a thorough security evaluation to assess its safety measures and potential vulnerabilities.
As industries increasingly adopt Claude Sonnet 4.5 for its autonomous capabilities, this security analysis aims to evaluate its safety features and identify areas for enhancement.
"Claude Sonnet 4.5 is the best coding model in the world, the strongest model for building complex agents, and the best model at using computers. It also shows substantial gains in reasoning and math."— Anthropic
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1 million tokens input • 1 million tokens output
autonomous software development, complex business task execution
• coding • agent building • real-world computer tasks
• Claude.ai • Claude API • Amazon Bedrock • Google Cloud Vertex AI
January 2025
Comprehensive analysis across 39 test categories, sorted by severity and pass rate:
Our security testing suite demonstrates varying levels of compliance across different categories. The Claude Sonnet 4.5 model's overall pass rate distribution shows 3 critical, 5 high, 15 medium, and 16 low severity findings.
Top performing areas include Methamphetamine Content (100%), Personal Attacks (100%), Dangerous Activity Content (100%). These categories demonstrate exceptional security practices and robust implementation.
Areas requiring attention include Entity Impersonation (0%), Religious Bias (80%), Profanity (80%). These categories present opportunities for improvement in security measures.
Tests for training data leaks through repetitive pattern exploitation that causes model divergence
Tests for fabrication of false or misleading information
Our evaluation included over 1,600 test probes across four security categories. The analysis revealed both strengths and areas requiring additional safety measures:
Protection against unauthorized access, data exposure, and system vulnerabilities
Assessment of compliance with legal requirements and prevention of illegal content
Prevention of harmful content and protection of user safety
Protection of brand integrity and prevention of misuse
OWASP Top 10 for LLMs (2025) and MITRE ATLAS represent the primary security assessment frameworks for large language models. OWASP focuses on critical deployment risks, while ATLAS maps adversarial techniques against AI systems, similar to the MITRE ATT&CK framework for traditional systems.
The Claude Sonnet 4.5 model's evaluation against these frameworks reveals several areas requiring attention across 4 identified findings. While Claude Sonnet 4.5 has no critical vulnerabilities, high-severity issues should be prioritized for improvement.
MITRE ATLAS identified Jailbreak as high-severity concerns.
39
96.0%
3
Tests for unauthorized impersonation of entities
Tests handling of profane or inappropriate language
Tests handling of religious content and bias
Tests for unauthorized actions beyond defined system boundaries
Tests handling of cybercrime-related content
Tests handling of political content and bias
Tests for direct PII exposure vulnerabilities
Tests for overreliance on system assumptions
Tests handling of Pliny prompt injections
Tests handling of violent crime content