AWS Bedrock Claude Cross Region Possible Inference Abuse
Last updated 2 days ago on 2026-07-17
About
This detection identifies potential cross-region inference abuse in AWS Bedrock Claude models. Cross-region inference abuse may indicate attempts to bypass regional restrictions, exfiltrate data, or perform unauthorized actions across different AWS regions.
- Platform
Splunk
- Tags
- Data Source: SplunkDomain: ApplicationRule Type: QueryOS: Any
- Severity
- medium
- Risk Score
- 47
- References
- https://aws.amazon.com/blogs/apn/unlocking-the-power-of-splunk-with-amazon-bedrock-an-agentic-ai-approach-to-build-customized-splunk-assistants-using-bedrock-agents/(external, opens in a new tab or window)https://help.splunk.com/en/splunk-observability-cloud/observability-for-ai/splunk-ai-infrastructure-monitoring/set-up-ai-infrastructure-monitoring/amazon-bedrock(external, opens in a new tab or window)https://research.splunk.com/stories/aws_bedrock_security/(external, opens in a new tab or window)https://docs.aws.amazon.com/bedrock/latest/userguide/model-invocation-logging.html(external, opens in a new tab or window)
- False Positives
- False positives may arise from legitimate use cases where users are accessing AWS Bedrock Claude models across different regions for valid reasons, such as multi-region deployments, testing, or development purposes. It is important to review the context of the detected events to determine if they represent actual abuse or benign usage.
- Source
- View on GitHub(external, opens in a new tab or window)
Definition
- Rule Language
- SPL
- Rule Type
- query
text code block:`aws_bedrock_claude` | rename "identity.arn" AS user_arn | rename "input.inputTokenCount" AS input_tokens | rename "output.outputTokenCount" AS output_tokens | rex field=user_arn "assumed-role/[^/]+/(?<user>[^\"]+)$" | rex field="input.inputBodyJson.metadata.user_id" "(?<session_user>user_[^_]+.*)" | eval input_tokens=tonumber(input_tokens) | eval output_tokens=tonumber(output_tokens) | eval token_ratio=round(output_tokens / max(input_tokens,1), 2) | eval model_short=replace(modelId,"^.*/","") | eval mismatch_detail=region." -> ".inferenceRegion | where isnotnull(user_arn) AND len(user_arn)>10 | where isnotnull(session_user) | where region!=inferenceRegion | where input_tokens>=2000 | table _time, user, user_arn, session_user, model_short, input_tokens, output_tokens, token_ratio, mismatch_detail, operation, host | sort - input_tokens | `aws_bedrock_claude_cross_region_possible_inference_abuse_filter`
View this rule on Splunk
This rule was sourced from the official Splunk public repository. View the original rule on GitHub(external, opens in a new tab or window).