Anthropic-Cybersecurity-Skills/skills/analyzing-cobalt-strike-beacon-configuration/references/standards.md

Standards and Frameworks Reference

Cobalt Strike Beacon Configuration Fields

Configuration TLV Types

Type ID	Field Name	Data Type	Description
0x0001	BeaconType	Short	0=HTTP, 1=Hybrid HTTP/DNS, 8=HTTPS, 10=TCP Bind
0x0002	Port	Short	C2 communication port
0x0003	SleepTime	Int	Beacon callback interval in milliseconds
0x0005	Jitter	Short	Percentage of sleep time randomization (0-99)
0x0008	C2Server	String	Comma-separated C2 domains/IPs
0x0009	UserAgent	String	HTTP User-Agent header value
0x000a	PostURI	String	URI for HTTP POST requests
0x000d	SpawnTo_x86	String	32-bit process to spawn for post-ex
0x000e	SpawnTo_x64	String	64-bit process to spawn for post-ex
0x001a	Watermark	Int	License watermark identifier
0x0024	PipeName	String	Named pipe for SMB beacon
0x001d	HostHeader	String	HTTP Host header value
0x0032	ProxyHostname	String	Proxy server address

XOR Encoding Scheme

• Cobalt Strike 3.x: XOR key = 0x69
• Cobalt Strike 4.x: XOR key = 0x2e
• Configuration blob size: 4096 bytes (typical)
• Encoding: Single-byte XOR across entire config blob

Stageless Beacon Structure

• PE with beacon code in .data section
• 4-byte XOR key applied to .data section content
• Configuration embedded after beacon code
• Reflective DLL loader prepended to beacon

MITRE ATT&CK Mappings

Cobalt Strike Techniques (S0154)

Technique	ID	Description
Application Layer Protocol	T1071.001	HTTP/HTTPS C2 communication
Encrypted Channel	T1573.002	AES-256 encrypted C2
Ingress Tool Transfer	T1105	Download additional payloads
Process Injection	T1055	Inject into spawned processes
Named Pipes	T1570	SMB beacon lateral movement
Service Execution	T1569.002	PSExec-style lateral movement
Reflective Code Loading	T1620	In-memory beacon loading

Malleable C2 Profile Structure

HTTP GET Block

http-get {
    set uri "/path";
    client {
        header "Accept" "text/html";
        metadata {
            base64url;
            prepend "session=";
            header "Cookie";
        }
    }
    server {
        header "Content-Type" "text/html";
        output {
            print;
        }
    }
}

HTTP POST Block

http-post {
    set uri "/submit";
    client {
        id {
            uri-append;
        }
        output {
            base64;
            print;
        }
    }
    server {
        output {
            print;
        }
    }
}

References

• Cobalt Strike Documentation
• Malleable C2 Profile Reference
• MITRE ATT&CK Cobalt Strike