Traffic Signaling:  Фильтры сокета

BPFDoor uses BPF bytecode to attach a filter to a network socket to view ICMP, UDP, or TCP packets coming through ports 22 (ssh), 80 (http), and 443 (https). When BPFDoor finds a packet containing its “magic” bytes, it parses out two fields and forks itself. The parent process continues to monitor filtered traffic while the child process executes the instructions from the parsed fields.(Citation: Sandfly BPFDoor 2022)(Citation: Deep Instinct BPFDoor 2023)

PITSTOP can listen and evaluate incoming commands on the domain socket, created by PITHOOK malware, located at `/data/runtime/cockpit/wd.fd` for a predefined magic byte sequence. PITSTOP can then duplicate the socket for further communication over TLS.(Citation: Mandiant Cutting Edge Part 3 February 2024)

Penquin installs a `TCP` and `UDP` filter on the `eth0` interface.(Citation: Leonardo Turla Penquin May 2020)

Employ network appliances and endpoint software to filter ingress, egress, and lateral network traffic. This includes protocol-based filtering, enforcing firewall rules, and blocking or restricting traffic based on predefined conditions to limit adversary movement and data exfiltration. This mitigation can be implemented through the following measures: Ingress Traffic Filtering: - Use Case: Configure network firewalls to allow traffic only from authorized IP addresses to public-facing servers. - Implementation: Limit SSH (port 22) and RDP (port 3389) traffic to specific IP ranges. Egress Traffic Filtering: - Use Case: Use firewalls or endpoint security software to block unauthorized outbound traffic to prevent data exfiltration and command-and-control (C2) communications. - Implementation: Block outbound traffic to known malicious IPs or regions where communication is unexpected. Protocol-Based Filtering: - Use Case: Restrict the use of specific protocols that are commonly abused by adversaries, such as SMB, RPC, or Telnet, based on business needs. - Implementation: Disable SMBv1 on endpoints to prevent exploits like EternalBlue. Network Segmentation: - Use Case: Create network segments for critical systems and restrict communication between segments unless explicitly authorized. - Implementation: Implement VLANs to isolate IoT devices or guest networks from core business systems. Application Layer Filtering: - Use Case: Use proxy servers or Web Application Firewalls (WAFs) to inspect and block malicious HTTP/S traffic. - Implementation: Configure a WAF to block SQL injection attempts or other web application exploitation techniques.