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How the CVE Works:
The vulnerability (CVE-2024-XXXX) in Helm arises due to insufficient recursion depth validation when parsing JSON Schema files in Helm charts. An attacker can craft a malicious chart containing a deeply nested JSON Schema with recursive references. When Helm processes this schema, it triggers uncontrolled recursion in the parser, exceeding the stack size limit and causing a stack overflow. This can crash the Helm process, leading to denial-of-service (DoS) or potential remote code execution (RCE) if memory corruption occurs. The issue stems from Helm’s YAML/JSON parser failing to enforce depth limits during schema validation.
DailyCVE Form:
Platform: Helm
Version: <3.17.3
Vulnerability: Stack Overflow
Severity: Critical
Date: 2024-XX-XX
What Undercode Say:
Exploitation:
1. Craft Malicious Chart:
schema.yaml
{"$ref": "/definitions/loop", "definitions": {"loop": {"$ref": "/definitions/loop"}}}
2. Deploy Exploit:
helm install malicious-chart ./malicious-chart
Detection:
1. Check Helm Version:
helm version --short | grep -q "v3.17.3" || echo "Vulnerable"
2. Scan Charts:
grep -r "\$ref" ./charts --include=".json" | wc -l
Mitigation:
1. Patch Helm:
helm upgrade --install helm https://helm.sh/helm-v3.17.3
2. Schema Validation:
import yaml
def validate_schema(schema, depth=0):
if depth > 100: raise Exception("Max depth exceeded")
if "$ref" in schema: validate_schema(resolve_ref(schema), depth+1)
Additional Checks:
- Kubernetes Audit Logs:
kubectl logs -l app=helm --tail=100 | grep -i "stack overflow"
- Resource Limits:
ulimit -s 8192 Set stack size limit
References:
References:
Reported By: https://github.com/advisories/GHSA-5xqw-8hwv-wg92
Extra Source Hub:
Undercode
