asrep2kirbi

Overview

Convert AS-REP (Authentication Server Reply) responses to .kirbi ticket format. This utility command processes AS-REP data extracted from network captures or other sources into usable Kerberos ticket files.

Syntax

Rubeus.exe asrep2kirbi /asrep:ASREP_DATA [options]

Required Parameters

asrep

string

required

Base64-encoded AS-REP response data

Optional Parameters

outfile

string

Save converted ticket to file

ptt

boolean

Pass-the-ticket (inject converted ticket)

Examples

# Convert AS-REP to kirbi format
Rubeus.exe asrep2kirbi /asrep:base64_asrep_data

# Convert and save to file
Rubeus.exe asrep2kirbi /asrep:asrep_data /outfile:converted.kirbi

# Convert and inject immediately
Rubeus.exe asrep2kirbi /asrep:asrep_data /ptt

AS-REP Data Sources

Data Acquisition

Network Captures:

Wireshark/tcpdump packet captures
AS-REP responses from KDC communications
Extracted from authentication exchanges
Base64-encoded packet data

Memory Dumps:

Process memory containing AS-REP responses
Cached authentication data
LSA memory structures
Application memory buffers

Log Analysis:

Authentication logs with embedded data
Debug logs from Kerberos implementations
Application logs with authentication details
Security event log analysis

Use Cases

Ticket Recovery

Data Conversion:

Convert captured AS-REP data to usable tickets
Process authentication data from various sources
Create .kirbi files from raw Kerberos data
Enable ticket analysis and manipulation

Forensic Analysis:

Analyze captured authentication exchanges
Reconstruct ticket data from fragments
Process historical authentication data
Support incident response activities

Integration Workflows

Capture and Conversion

Complete Workflow:

# 1. Capture AS-REP from network traffic
# Use Wireshark, tcpdump, or other packet capture tools

# 2. Extract AS-REP data as base64
# Process packet capture to extract AS-REP portion

# 3. Convert to .kirbi format
Rubeus.exe asrep2kirbi /asrep:captured_asrep_data /outfile:recovered.kirbi

# 4. Use recovered ticket
Rubeus.exe ptt /ticket:recovered.kirbi

Memory Analysis

Memory-Based Recovery:

# 1. Extract AS-REP data from memory dumps
# Use memory analysis tools to locate AS-REP structures

# 2. Convert extracted data
Rubeus.exe asrep2kirbi /asrep:memory_extracted_data

# 3. Analyze converted ticket
Rubeus.exe describe /ticket:converted.kirbi

Technical Considerations

AS-REP Structure

Response Components:

KDC certificate information
Encrypted TGT data
Session key information
Client and server principal names
Ticket validity periods

Conversion Process:

Parse AS-REP ASN.1 structure
Extract TGT components
Reconstruct .kirbi format
Maintain ticket integrity

Data Validation

Quality Assurance

Verification Steps:

Validate AS-REP structure integrity
Check encryption and encoding
Verify ticket component completeness
Test converted ticket functionality

Error Handling:

Malformed AS-REP data
Incomplete packet captures
Encoding issues
Structural corruption

asreproast - Generate AS-REP data for conversion
describe - Analyze converted tickets
ptt - Use converted tickets
kirbi - Alternative ticket format operations

Getting Started

Ticket Operations

Attack Techniques

Miscellaneous

Overview

Syntax

Required Parameters

Optional Parameters

Examples

AS-REP Data Sources

Use Cases

Integration Workflows

Technical Considerations

Data Validation

​Overview

​Syntax

​Required Parameters

​Optional Parameters

​Examples

​AS-REP Data Sources

​Use Cases

​Integration Workflows

​Technical Considerations

​Data Validation

​Related Commands

Overview

Syntax

Required Parameters

Optional Parameters

Examples

AS-REP Data Sources

Use Cases

Integration Workflows

Technical Considerations

Data Validation

Related Commands