Telco Security

Security Monitoring & SIEM Guide

Comprehensive guide to implementing security monitoring, SIEM solutions, and threat detection for telecommunications networks

Security Monitoring Fundamentals
Core concepts and architecture for telecommunications security monitoring

Monitoring Architecture

Data Collection Layer
NetworkSS7, Diameter, GTP, SIP traffic capture
SystemsHLR, HSS, MSC, SGSN, GGSN logs
SecurityFirewall, IDS/IPS, authentication logs
ApplicationsBilling, provisioning, management systems
Processing Layer
NormalizationLog parsing and standardization
EnrichmentThreat intelligence integration
CorrelationMulti-source event correlation
AnalyticsBehavioral analysis and ML detection

Key Monitoring Objectives

Threat Detection

Identify SS7, Diameter, GTP, and SIM-based attacks in real-time

Anomaly Detection

Detect unusual patterns in signaling traffic and subscriber behavior

Compliance Monitoring

Ensure adherence to GSMA, 3GPP, and regulatory requirements

Performance Monitoring

Track network performance and identify degradation

SIEM Implementation
Deploy and configure SIEM solutions for telecommunications security

SIEM Platform Selection

Commercial Solutions

Splunk Enterprise Security

Industry-leading SIEM with telecom-specific apps

IBM QRadar

Advanced threat detection and compliance

LogRhythm NextGen SIEM

Unified security analytics platform

Open Source Solutions

Elastic Security (ELK Stack)

Scalable log management and analytics

Wazuh

Open source security monitoring platform

OSSIM (AlienVault)

Unified security management

Telecom-Specific

Adaptive Mobile Threat Intelligence

SS7/Diameter threat detection

Positive Technologies SS7 Firewall

Signaling security monitoring

Mobileum Active Intelligence

Network security analytics

Implementation Phases

Phase 1: Planning & Design (4-6 weeks)

  • Define monitoring requirements and use cases
  • Identify log sources and data collection points
  • Design SIEM architecture and sizing
  • Plan integration with existing security tools

Phase 2: Deployment (6-8 weeks)

  • Install SIEM infrastructure (collectors, indexers, search heads)
  • Configure log sources and data inputs
  • Set up data retention and archiving policies
  • Implement high availability and disaster recovery

Phase 3: Configuration (4-6 weeks)

  • Create parsing rules and field extractions
  • Develop correlation rules and alerts
  • Build dashboards and reports
  • Integrate threat intelligence feeds

Phase 4: Tuning & Optimization (Ongoing)

  • Fine-tune correlation rules to reduce false positives
  • Optimize search performance and indexing
  • Update detection rules based on new threats
  • Conduct regular effectiveness reviews
Threat Detection Rules
Correlation rules and detection logic for telecommunications threats

SS7 Attack Detection

Location Tracking Detection

Detection Logic:

IF (MAP_PSI OR MAP_ATI) FROM unknown_GT
AND frequency > 5 requests/hour
THEN ALERT "Potential SS7 Location Tracking"

Detects excessive location queries from unauthorized global titles

SMS Interception Detection

Detection Logic:

IF MAP_SRI_SM FROM foreign_network
AND subscriber_location != foreign_network
THEN ALERT "Potential SMS Interception"

Identifies suspicious SMS routing information requests

GTP Attack Detection

GTP Tunneling Attack

Detection Logic:

IF GTP_CREATE_PDP_CONTEXT
AND source_IP NOT IN authorized_SGSN_list
THEN ALERT "Unauthorized GTP Tunnel Creation"

Detects unauthorized GTP tunnel establishment attempts

IMSI Spoofing Detection

Detection Logic:

IF same_IMSI appears in multiple_locations
AND time_difference < 5 minutes
THEN ALERT "Potential IMSI Spoofing"

Identifies impossible travel scenarios indicating IMSI spoofing

SIM Swap Detection

Suspicious SIM Swap Activity

Detection Logic:

IF SIM_SWAP_EVENT
AND (high_value_account OR recent_password_reset)
AND new_device_location != previous_location
THEN ALERT "High-Risk SIM Swap Detected"

Identifies high-risk SIM swap events targeting valuable accounts

Security Analytics
Advanced analytics and machine learning for threat detection

Behavioral Analytics

User Behavior Analytics (UBA)

Baseline Establishment:

  • Normal call patterns and data usage
  • Typical roaming behavior
  • Standard service usage patterns
  • Geographic movement patterns

Anomaly Detection:

  • Sudden changes in usage patterns
  • Unusual roaming activity
  • Abnormal service requests
  • Impossible travel scenarios
Network Behavior Analytics (NBA)

Traffic Analysis:

  • Signaling traffic volume patterns
  • Protocol distribution analysis
  • Inter-network communication patterns
  • Peak usage time identification

Threat Indicators:

  • Unusual signaling spikes
  • Abnormal protocol usage
  • Suspicious inter-network queries
  • DDoS attack patterns

Machine Learning Models

Supervised Learning Models
ClassificationCategorize events as benign or malicious based on labeled training data
RegressionPredict risk scores for security events

Use Cases: SS7 attack classification, fraud detection, threat severity scoring

Unsupervised Learning Models
ClusteringGroup similar events to identify attack patterns
Anomaly DetectionIdentify outliers and unusual behavior without labeled data

Use Cases: Zero-day threat detection, insider threat identification, new attack pattern discovery

SOC Operations
Security Operations Center procedures and best practices

SOC Team Structure

Tier 1: Monitoring

Responsibilities:

  • 24/7 alert monitoring
  • Initial triage and classification
  • Basic incident response
  • Escalation to Tier 2

Skills Required:

SIEM operation, basic networking, incident handling

Tier 2: Analysis

Responsibilities:

  • Deep dive investigation
  • Threat hunting
  • Correlation rule development
  • Incident response coordination

Skills Required:

Advanced threat analysis, SS7/Diameter expertise, forensics

Tier 3: Engineering

Responsibilities:

  • SIEM architecture and tuning
  • Advanced threat research
  • Security tool integration
  • Process improvement

Skills Required:

Security engineering, automation, threat intelligence

Alert Response Workflow

Critical (P1) - Response Time: 15 minutes

  • Active SS7/Diameter attack in progress
  • Mass SIM swap fraud campaign
  • Network-wide service disruption
  • Data breach or exfiltration

High (P2) - Response Time: 1 hour

  • Targeted subscriber attack
  • Suspicious signaling activity
  • Unauthorized access attempts
  • Policy violations

Medium (P3) - Response Time: 4 hours

  • Anomalous behavior patterns
  • Configuration issues
  • Compliance violations
  • Performance degradation

Low (P4) - Response Time: 24 hours

  • Informational alerts
  • Trend analysis findings
  • Routine security events
  • Documentation updates

Key Performance Indicators (KPIs)

Operational Metrics
Mean Time to Detect (MTTD)< 5 minutes
Mean Time to Respond (MTTR)< 15 minutes
Alert VolumeTrack daily
False Positive Rate< 5%
Effectiveness Metrics
Threat Detection Rate> 95%
Incident Containment Time< 1 hour
Coverage of Attack Vectors> 90%
SOC Analyst ProductivityTrack monthly
Related Resources
Threat Intelligence Guide →Incident Response Guide →Penetration Testing Guide →SS7 Attack Vectors →
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