CVE-2021-1579
📋 TL;DR
This vulnerability allows authenticated remote attackers with Administrator read-only credentials to elevate privileges to Administrator with write privileges on Cisco APIC and Cloud APIC systems. Attackers can exploit insufficient RBAC controls by sending specific API requests. Organizations using affected Cisco APIC/Cloud APIC versions are at risk.
💻 Affected Systems
- Cisco Application Policy Infrastructure Controller (APIC)
- Cisco Cloud Application Policy Infrastructure Controller (Cloud APIC)
📦 What is this software?
Application Policy Infrastructure Controller by Cisco
View all CVEs affecting Application Policy Infrastructure Controller →
Application Policy Infrastructure Controller by Cisco
View all CVEs affecting Application Policy Infrastructure Controller →
Application Policy Infrastructure Controller by Cisco
View all CVEs affecting Application Policy Infrastructure Controller →
Cloud Application Policy Infrastructure Controller by Cisco
View all CVEs affecting Cloud Application Policy Infrastructure Controller →
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to modify configurations, deploy malicious policies, exfiltrate sensitive data, or disrupt network operations.
Likely Case
Privilege escalation enabling unauthorized configuration changes, policy manipulation, and potential lateral movement within the network.
If Mitigated
Limited impact if proper network segmentation, API access controls, and monitoring are implemented to detect suspicious API activity.
🎯 Exploit Status
Exploitation requires authenticated access with read-only admin credentials and knowledge of specific API endpoints.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.2(1g) and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-capic-chvul-CKfGYBh8
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download and install APIC/Cloud APIC version 5.2(1g) or later from Cisco Software Center. 3. Reboot the system after installation. 4. Verify successful upgrade and functionality.
🔧 Temporary Workarounds
Restrict API Access
allLimit API endpoint access to trusted IP addresses and implement strict network segmentation for APIC management interfaces.
Configure ACLs on network devices to restrict access to APIC API endpoints (typically TCP/443)
Review Admin Accounts
allAudit and minimize Administrator read-only accounts, implement strong authentication, and monitor for suspicious activity.
Review APIC user accounts: 'acidiag fnvread' or via GUI under Admin > AAA
🧯 If You Can't Patch
- Implement strict network segmentation to isolate APIC management interfaces from untrusted networks
- Enable detailed API logging and monitor for suspicious API requests from read-only admin accounts
🔍 How to Verify
Check if Vulnerable:
Check APIC version via GUI (System > Controller > Firmware) or CLI: 'acidiag version' or 'show version'Check Version:
acidiag version | grep -i versionVerify Fix Applied:
Verify version is 5.2(1g) or later using same commands and test that read-only admin accounts cannot perform write operations📡 Detection & Monitoring
Log Indicators:
- API requests from read-only admin accounts attempting write operations
- Unusual privilege escalation events in audit logs
- Failed then successful API authorization attempts
Network Indicators:
- Unusual API traffic patterns to APIC management interfaces
- Multiple API requests from single read-only admin account
SIEM Query:
source="apic" AND (event_type="api_request" AND user_role="read-only-admin" AND operation="write")