mcpacket

# Analysis Guides Learn how to effectively analyze network traffic using mcpcap's specialized capabilities. ## DNS Analysis Fundamentals ### Understanding DNS Packet Structure DNS packets contain several key components that mcpcap analyzes: - **Header**: Contains flags, response codes, and packet metadata - **Questions**: What domain names are being queried - **Answers**: The responses to DNS queries - **Authority**: Authoritative name server information - **Additional**: Extra resource records ### Key Metrics to Monitor **Query/Response Ratio** - Normal: ~1:1 ratio (each query gets a response) - Suspicious: Many queries without responses (DNS tunneling) - Problem: High query count with NXDOMAIN responses **Unique Domains** - Normal: Varied domain names from typical browsing - Suspicious: Random-looking domain names (DGA malware) - Problem: Queries to non-existent domains **Query Frequency** - Normal: Sporadic queries matching user activity - Suspicious: Regular intervals (beaconing behavior) - Problem: Excessive queries indicating DNS recursion loops ## Security Analysis ### Identifying Malicious Activity **Domain Generation Algorithm (DGA) Detection** Look for domains with these characteristics: - Long random-looking strings - Excessive consonants or numbers - Unusual TLD combinations - High query frequency to non-existent domains ```json { "suspicious_patterns": [ "a8f3k2l9m.com", "xj9pk2lmn4.biz", "random123abc.tk" ] } ``` **DNS Tunneling Indicators** - Unusually long DNS queries (>100 characters) - High volume of TXT record queries - Encoded data in subdomain names - Regular query intervals **Command & Control (C2) Communication** - Periodic DNS queries to specific domains - Consistent query timing patterns - Queries to recently registered domains - Non-standard DNS record types ### Security Analysis Workflow 1. **Initial Assessment** ``` Use analyze_dns_packets() to get overview statistics Look for unusual domain counts or query patterns ``` 2. **Pattern Recognition** ``` Filter for domains with suspicious characteristics Analyze query timing and frequency Check for encoded data in domain names ``` 3. **Threat Classification** ``` Compare domains against threat intelligence Identify potential malware families Assess impact and scope ``` 4. **Evidence Collection** ``` Document all suspicious queries with timestamps Extract communication patterns Prepare indicators of compromise (IOCs) ``` ## Network Troubleshooting ### DNS Performance Issues **High Latency Symptoms** - Long delays between queries and responses - Timeout errors and retransmissions - User complaints about slow web browsing **Diagnostic Steps** 1. Measure query response times 2. Identify slow DNS servers 3. Check for network path issues 4. Analyze query distribution **Common Causes** - Overloaded DNS servers - Network congestion - Misconfigured DNS forwarding - Geographic distance to DNS servers ### Resolution Failures **NXDOMAIN Analysis** - Track domains that don't exist - Identify typos or misconfigured applications - Detect DNS poisoning attempts **Timeout Investigation** - Find queries without responses - Identify unreachable DNS servers - Trace network connectivity issues ### Troubleshooting Workflow 1. **Baseline Establishment** ``` Analyze normal DNS traffic patterns Document typical response times Identify peak usage periods ``` 2. **Problem Identification** ``` Compare current traffic to baseline Identify deviations in timing or patterns Locate specific failure points ``` 3. **Root Cause Analysis** ``` Trace queries from client to server Check for intermediate failures Analyze server response patterns ``` 4. **Solution Implementation** ``` Address identified bottlenecks Optimize DNS server configuration Implement caching strategies ``` ## Forensic Investigation ### Timeline Analysis **Chronological Reconstruction** - Order all DNS events by timestamp - Correlate queries with known incident times - Identify patterns in timing and frequency **Event Correlation** - Match DNS queries to system events - Connect domain lookups to file executions - Link network activity to user actions ### Evidence Collection **Chain of Custody** - Document PCAP file sources and timestamps - Preserve original capture integrity - Maintain detailed analysis logs **Data Extraction** - Export suspicious queries with full metadata - Document response codes and timing - Preserve packet-level details for court proceedings ### Attribution Analysis **Source Identification** - Map IP addresses to systems or users - Analyze query patterns for behavioral signatures - Correlate with other network evidence **Impact Assessment** - Determine scope of DNS-based compromise - Identify potential data exfiltration - Assess ongoing security risks ### Forensic Workflow 1. **Evidence Preservation** ``` Create forensic copies of PCAP files Document analysis environment Maintain chain of custody logs ``` 2. **Timeline Construction** ``` Extract all DNS events with timestamps Correlate with incident indicators Build comprehensive activity timeline ``` 3. **Pattern Analysis** ``` Identify recurring DNS queries Map communication patterns Analyze behavioral signatures ``` 4. **Report Generation** ``` Document findings with timestamps Include technical details and evidence Prepare court-ready documentation ``` ## Advanced Techniques ### Statistical Analysis **Frequency Analysis** - Query volume over time - Domain popularity rankings - Response code distributions **Anomaly Detection** - Identify outliers in query patterns - Detect unusual domain structures - Flag abnormal response behaviors ### Data Correlation **Multi-source Analysis** - Combine DNS data with other logs - Correlate with threat intelligence feeds - Cross-reference with known indicators **Behavioral Baselines** - Establish normal DNS patterns - Create user/system profiles - Detect deviations from baseline ## Best Practices ### Data Collection - Capture complete DNS conversations (queries + responses) - Include sufficient time windows for pattern analysis - Maintain high-resolution timestamps - Preserve all DNS record types ### Analysis Approach - Start with overview statistics before diving deep - Use multiple analysis techniques for validation - Document methodology and findings - Maintain objectivity in threat assessment ### Tool Usage - Leverage mcpcap's specialized prompts for guidance - Combine automated analysis with manual review - Use reference resources for DNS technical details - Validate findings with additional tools when possible ### Reporting - Include both technical details and executive summaries - Provide actionable recommendations - Document confidence levels in findings - Maintain professional presentation standards ## DHCP Analysis Fundamentals ### Understanding DHCP Packet Structure DHCP packets contain several key components: - **Header**: Message type, transaction ID, flags - **Client/Server Addresses**: IP address assignments - **Options**: Network configuration parameters - **Message Types**: DISCOVER, OFFER, REQUEST, ACK, NAK, RELEASE ### Key Metrics to Monitor **DHCP Transaction Flow** - Normal: Complete 4-way handshake (DISCOVER→OFFER→REQUEST→ACK) - Problem: Incomplete transactions or excessive retries - Security: Unexpected message types or timing **IP Address Management** - Normal: Organized lease allocation and renewal - Problem: Address pool exhaustion or conflicts - Security: Unauthorized DHCP servers or spoofing ### Security Indicators **Rogue DHCP Servers** - Multiple DHCP servers responding - Unexpected server IP addresses - Suspicious network configuration options **DHCP Attacks** - DHCP starvation (excessive DISCOVER requests) - Malicious DHCP options (DNS poisoning) - MAC address spoofing patterns ## ICMP Analysis Fundamentals ### Understanding ICMP Packet Structure ICMP packets provide network diagnostics: - **Type/Code**: Message type and sub-type - **Echo Request/Reply**: Ping functionality - **Error Messages**: Network unreachable, TTL exceeded - **Timestamp**: Round-trip time analysis ### Key Metrics to Monitor **Ping Analysis** - Normal: Regular echo request/reply pairs - Problem: High packet loss or excessive latency - Security: ICMP tunneling or covert channels **Network Diagnostics** - Normal: Occasional error messages - Problem: Excessive unreachable messages - Security: Network reconnaissance patterns ### Security Indicators **ICMP-based Attacks** - ICMP flood attacks - ICMP tunneling for data exfiltration - Network reconnaissance and scanning - Covert channel communication