Network Security Audit

When to Use

• Security posture assessment for compliance (SOC2, PCI-DSS, NIST, CIS)
• Pre-deployment security review
• Incident response — checking for unauthorized access or configuration
• Hardening audit for new devices
• Periodic security validation

Security Audit Procedure

Step 1: Pull Running Configuration

Always start by capturing the full running config for analysis:

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_show_running_config '{"device_name":"R1"}'

Scan the full config for the checks below.

Step 2: Management Plane Hardening

Check these items in the running config:

| Check | What to Look For | Finding If Missing | |-------|------------------|--------------------| | SSH version | ip ssh version 2 | CRITICAL: SSHv1 vulnerable to MITM | | Telnet disabled | No transport input telnet on VTY lines | CRITICAL: Telnet sends cleartext credentials | | VTY ACL | access-class on VTY lines | HIGH: Unrestricted management access | | Console timeout | exec-timeout on console (not 0 0) | MEDIUM: Unattended console sessions | | VTY timeout | exec-timeout on VTY lines (not 0 0) | MEDIUM: Stale management sessions | | Password encryption | service password-encryption | MEDIUM: Type 0 passwords visible | | Enable secret | enable secret (not enable password) | HIGH: Enable password uses weak hash | | Login banner | banner login or banner motd | LOW: Legal/compliance requirement | | HTTP server disabled | no ip http server | MEDIUM: Unnecessary attack surface | | HTTPS server | ip http secure-server if web management needed | MEDIUM: Use HTTPS not HTTP | | Aux port disabled | no exec on aux line | LOW: Unused port open |

Step 3: AAA Configuration

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_run_show_command '{"device_name":"R1","command":"show aaa servers"}'

AAA checks in running config:

• aaa new-model enabled
• aaa authentication login configured (not just local)
• aaa authorization exec configured
• aaa accounting configured for commands and connections
• TACACS+ or RADIUS server defined with encryption
• Local fallback account exists (in case AAA server unreachable)
• aaa authentication enable uses enable secret not enable password

Step 4: Access Control Lists

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_run_show_command '{"device_name":"R1","command":"show ip access-lists"}'

ACL analysis:

• Check hit counts — ACEs with 0 matches may be unnecessary or misplaced
• Look for overly permissive rules (permit ip any any)
• Verify explicit deny at the end with logging (deny ip any any log)
• Check ACL is applied to the correct interface and direction
• Verify VTY access-class restricts management to known networks
• Look for ACLs referenced in route-maps, NAT, or other features

Step 5: Control Plane Policing (CoPP)

Check in running config for:

• control-plane section with service-policy
• CoPP policy-map classifying and rate-limiting traffic to the CPU
• Protection against: ICMP floods, TTL-expired floods, fragmentation attacks, ARP storms

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_run_show_command '{"device_name":"R1","command":"show policy-map control-plane"}'

Step 6: Routing Protocol Security

OSPF authentication:

• Check for ip ospf authentication message-digest on interfaces
• Or area-level: area X authentication message-digest
• Verify ip ospf message-digest-key is configured

BGP security:

• neighbor X password (MD5 authentication)
• neighbor X ttl-security hops N (GTSM — Generalized TTL Security Mechanism)
• neighbor X prefix-list or neighbor X maximum-prefix (prefix limits)
• Check for bogon filtering on eBGP peers

EIGRP authentication:

• Named mode: af-interface with authentication mode md5 and authentication key-chain
• Classic mode: ip authentication mode eigrp and ip authentication key-chain eigrp

Step 7: Infrastructure Security

Check in running config:

| Feature | Config | Purpose | |---------|--------|---------| | uRPF | ip verify unicast source reachable-via rx | Anti-spoofing | | TCP keepalives | service tcp-keepalives-in, service tcp-keepalives-out | Dead session cleanup | | CDP restricted | no cdp enable on external interfaces | Information leak prevention | | LLDP restricted | no lldp transmit / no lldp receive on external | Information leak prevention | | IP source routing disabled | no ip source-route | Prevent source-routed attacks | | Directed broadcast disabled | no ip directed-broadcast per interface | Smurf attack prevention | | ICMP redirects disabled | no ip redirects per interface | MITM prevention | | Proxy ARP disabled | no ip proxy-arp on external interfaces | ARP spoofing prevention | | Gratuitous ARP | no ip gratuitous-arps | ARP cache poisoning prevention | | IP unreachables limited | no ip unreachables on external | Reconnaissance prevention | | Timestamps | service timestamps log datetime msec localtime | Forensics | | Logging buffer | logging buffered with adequate size | Event capture | | Remote logging | logging host X.X.X.X | Centralized log collection |

Step 8: Encryption & Credentials

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_run_show_command '{"device_name":"R1","command":"show crypto key mypubkey rsa"}'

Check:

• RSA key size >= 2048 bits (CRITICAL if < 1024)
• SSH version 2 only
• No Type 0 (cleartext) passwords in running config
• Enable secret uses Type 8 or Type 9 (scrypt) if available
• SNMP community strings are not "public" or "private"
• SNMPv3 preferred over v2c

Step 9: SNMP Security

bash
PYATS_TESTBED_PATH=$PYATS_TESTBED_PATH python3 $MCP_CALL "${PYATS_PYTHON:-python3} -u $PYATS_MCP_SCRIPT" pyats_run_show_command '{"device_name":"R1","command":"show snmp"}'

Checks:

• No default community strings (public, private, cisco)
• RO communities have ACL restricting source
• RW communities have ACL restricting source (or don't exist at all)
• SNMPv3 with authPriv preferred
• SNMP traps configured to central monitoring

Security Report Format

Device: R1 | IOS-XE 17.x.x
Security Audit Date: YYYY-MM-DD

CRITICAL FINDINGS (Fix Immediately):
  1. [C-001] SSHv1 enabled — upgrade to SSH version 2 only
  2. [C-002] No VTY access-class — management plane exposed

HIGH FINDINGS (Fix This Week):
  3. [H-001] No OSPF authentication on Gi1 — route injection risk
  4. [H-002] SNMP community 'public' with no ACL

MEDIUM FINDINGS (Fix This Month):
  5. [M-001] No CoPP policy — CPU vulnerable to floods
  6. [M-002] HTTP server enabled — disable or restrict

LOW / INFORMATIONAL:
  7. [L-001] No login banner configured
  8. [I-001] CDP enabled globally (acceptable on internal interfaces)

Summary: 2 Critical | 2 High | 2 Medium | 2 Low

ISE Integration (MISSION02 Enhancement)

When ISE is available ($ISE_MCP_SCRIPT is set), extend the security audit with identity verification:

Verify Device is Registered as NAD

Check that the device is registered in ISE as a Network Access Device:

bash
ISE_BASE=$ISE_BASE USERNAME=$ISE_USERNAME PASSWORD=$ISE_PASSWORD python3 $MCP_CALL "python3 -u $ISE_MCP_SCRIPT" network_devices '{}'

Flags:

• Device not registered as NAD → CRITICAL: Not participating in ISE enforcement
• Device registered but no RADIUS/TACACS config on device → HIGH: ISE configured but device not using it

Check Active Sessions on Device

bash
ISE_BASE=$ISE_BASE USERNAME=$ISE_USERNAME PASSWORD=$ISE_PASSWORD python3 $MCP_CALL "python3 -u $ISE_MCP_SCRIPT" active_sessions '{}'

Filter sessions for this device's IP to see authenticated endpoints.

NVD CVE Vulnerability Scan

After Step 1 (show version), extract the IOS-XE version and scan for known vulnerabilities:

bash
python3 $MCP_CALL "npx -y nvd-cve-mcp-server" search_cves '{"keyword":"Cisco IOS XE 17.9.4","resultsPerPage":10}'

For each CVE found:

1. Check CVSS score (flag CVSS >= 7.0)
2. Cross-reference running config for exposure (e.g., CVE requires HTTP server → check if ip http server is configured)
3. Produce exposure correlation: CVE + running-config = actual risk

Severity mapping:

• CVSS >= 9.0 → CRITICAL
• CVSS >= 7.0 → HIGH
• CVSS >= 4.0 → MEDIUM
• CVSS < 4.0 → LOW

Fleet-Wide Security Audit (pCall)

Run the full 9-step audit on ALL devices simultaneously using multiple exec commands. Aggregate findings across the fleet and sort by severity for prioritized remediation.

GAIT Audit Trail

Record the security audit in GAIT:

bash
python3 $MCP_CALL "python3 -u $GAIT_MCP_SCRIPT" gait_record_turn '{"input":{"role":"assistant","content":"Security audit on R1: 2 CRITICAL (no enable secret, telnet enabled), 2 HIGH, 2 MEDIUM, 2 LOW findings.","artifacts":[]}}'