Kubernetes Nginx Ingress RFI
Description
The following analytic detects remote file inclusion (RFI) attacks targeting Kubernetes Nginx ingress controllers. It leverages Kubernetes logs from the Nginx ingress controller, parsing fields such as remote_addr
, request
, and url
to identify suspicious activity. This activity is significant because RFI attacks can allow attackers to execute arbitrary code or access sensitive files on the server. If confirmed malicious, this could lead to unauthorized access, data exfiltration, or further compromise of the Kubernetes environment.
- Type: TTP
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2024-05-19
- Author: Patrick Bareiss, Splunk
- ID: fc5531ae-62fd-4de6-9c36-b4afdae8ca95
Annotations
Kill Chain Phase
- Exploitation
NIST
- DE.CM
CIS20
- CIS 13
CVE
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`kubernetes_container_controller`
| rex field=_raw "^(?<remote_addr>\S+)\s+-\s+-\s+\[(?<time_local>[^\]]*)\]\s\"(?<request>[^\"]*)\"\s(?<status>\S*)\s(?<body_bytes_sent>\S*)\s\"(?<http_referer>[^\"]*)\"\s\"(?<http_user_agent>[^\"]*)\"\s(?<request_length>\S*)\s(?<request_time>\S*)\s\[(?<proxy_upstream_name>[^\]]*)\]\s\[(?<proxy_alternative_upstream_name>[^\]]*)\]\s(?<upstream_addr>\S*)\s(?<upstream_response_length>\S*)\s(?<upstream_response_time>\S*)\s(?<upstream_status>\S*)\s(?<req_id>\S*)"
| rex field=request "^(?<http_method>\S+)?\s(?<url>\S+)\s"
| rex field=url "(?<dest_ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})"
| search dest_ip=*
| rename remote_addr AS src_ip, upstream_status as status, proxy_upstream_name as proxy
| eval phase="operate"
| eval severity="medium"
| stats count min(_time) as firstTime max(_time) as lastTime by src_ip, dest_ip status, url, http_method, host, http_user_agent, proxy, phase, severity
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `kubernetes_nginx_ingress_rfi_filter`
Macros
The SPL above uses the following Macros:
kubernetes_nginx_ingress_rfi_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- raw
How To Implement
You must ingest Kubernetes logs through Splunk Connect for Kubernetes.
Known False Positives
unknown
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
49.0 | 70 | 70 | Remote File Inclusion Attack detected on $host$ |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
- https://github.com/splunk/splunk-connect-for-kubernetes
- https://www.invicti.com/blog/web-security/remote-file-inclusion-vulnerability/
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 4