[Bug] [Security] Vulnerability Report: Authentication Bypass in SafeLine WAF Management Interface

[Xyborg]

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Summary

A configuration-based authentication bypass vulnerability exists in the SafeLine WAF management interface that disables authentication when the NO_AUTH environment variable is set during deployment.

Vulnerability Details

Severity: Medium
CVSS Score: 6.6 (Medium)
CWE: CWE-287 (Improper Authentication)
Affected Component: SafeLine Management Web Server
Affected File: management/webserver/main.go

Description

The SafeLine management web server contains logic that bypasses authentication middleware when any NO_AUTH environment variable is present with a non-empty value . This appears to be intended for development or testing purposes but creates a potential security risk in production deployments.

Impact

If exploited through deployment configuration, this vulnerability would provide:

• Administrative access to protected API endpoints
• Control over website configuration and SSL certificate management
• Ability to modify WAF policy rules and security settings

Attack Scenarios

This vulnerability requires access to the deployment environment and is exploitable in these scenarios:

1. Supply Chain Compromise: Malicious modification of deployment scripts or Docker Compose files
2. Insider Threats: Intentional misuse by personnel with deployment access
3. CI/CD Pipeline Compromise: Injection through compromised deployment pipelines
4. Configuration Management Issues: Accidental inclusion in production deployments

Proof of Concept

# In Docker Compose deployment
environment:
  - NO_AUTH=1

# Or via environment variable
export NO_AUTH=true

Recommended Fixes

Option 1: Complete Removal (Recommended)

Remove the authentication bypass logic entirely:

limitedRouters := r.Group("/api")
limitedRouters.Use(middleware.AuthRequired)

Option 2: Development Environment Restriction

If needed for development, restrict to development environments:

if os.Getenv("ENVIRONMENT") == "development" && os.Getenv("NO_AUTH") != "" {
    logger.Warn("No auth - development mode only")
} else {
    limitedRouters.Use(middleware.AuthRequired)
}

CVSS v3.1 Breakdown

• Attack Vector: Local (L) - requires deployment environment access
• Attack Complexity: Low (L) - simple configuration change
• Privileges Required: High (H) - needs deployment privileges
• User Interaction: None (N)
• Scope: Changed (C) - affects entire WAF system
• Impact: High (H) for confidentiality, integrity, and availability

Base Score: 6.6 (Medium)

Timeline

• Discovery Date: 28.09.2025
• Vendor Notification: 28.09.2025

References

• SafeLine Repository: https://github.com/chaitin/SafeLine
• CWE-287: https://cwe.mitre.org/data/definitions/287.html

Credit

Discovered by: Martin Aberastegue / Torito

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Note: While this vulnerability requires privileged access to exploit, it represents a configuration security risk that should be addressed to maintain defense-in-depth principles for a security product.

Citations

File: management/webserver/main.go (L162-167)

	noAuth, existed := os.LookupEnv("NO_AUTH")
	if existed && len(noAuth) >= 0 {
		logger.Warn("No auth")
	} else {
		limitedRouters.Use(middleware.AuthRequired)
	}

File: management/webserver/main.go (L174-188)

	limitedRouters.GET(api.User, api.GetUser)

	limitedRouters.GET(api.DetectLogList, api.GetDetectLogList)
	limitedRouters.GET(api.DetectLogDetail, api.GetDetectLogDetail)

	limitedRouters.POST(api.Website, api.PostWebsite)
	limitedRouters.PUT(api.Website, api.PutWebsite)
	limitedRouters.DELETE(api.Website, api.DeleteWebsite)
	limitedRouters.GET(api.Website, api.GetWebsite)

	limitedRouters.POST(api.UploadSSLCert, api.PostUploadSSLCert)
	limitedRouters.POST(api.SSLCert, api.PostSSLCert)

	limitedRouters.POST(api.PolicyRule, api.PostPolicyRule)
	limitedRouters.PUT(api.PolicyRule, api.PutPolicyRule)