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Intro

CyberDefenders.org, hosted a fun 24-hr reversing CTF. For those that don’t know about CyberDefenders they host a platform deticated to training BlueTeam skills: Incident response, digital forensics, security analysts, etc). If you are used to VulnHub and Hack-the-box, these services are typically geared more towards redteaming and penetration testing. This is where CyberDefenders stand out!

Walkthrough

A simple pcap analysis is all thats needed for the first few questions…

1) What is the attacker’s IP address?

Answer:

98.114.205.102

2) What is the target’s IP address?

Answer:

192.150.11.111

3) Provide the country code for the attacker’s IP address (a.k.a geo-location).

Hint:

  • OSINT
  • whois

Answer:

US

4) How many TCP sessions are present in the captured traffic?

Wireshark - Statistics - Destinations & Ports

Answer:

5

5) How long did it take to perform the attack (in seconds)?

Hint:

  • Capture is 24sec
  • There are few seconds of legitimate traffic either side of the attack traffic

Answer:

16

7) Provide the CVE number of the exploited vulnerability.

Hint:

  • Packet 38
  • description field a ‘DsROLEUpgradeDownLevelServer’
  • Google

Answer:

CVE-2003-0533

8) Which protocol was used to carry over the exploit?

Answer:

SMB

9) Which protocol did the attacker use to download additional malicious files to the target system?

Answer:

ftp

10) What is the name of the downloaded malware?

Answer:

ssms.exe

11) The attacker’s server was listening on a specific port. Provide the port number.

Answer:

8884

12) When was the involved malware first submitted to VirusTotal for analysis? Format: YYYY-MM-DD

Hint:

  • Extract the sample
  • get hash
  • VirusTotal - Details - History Link

Answer:

2007-06-27 

13) What is the key used to encode the shellcode?

Hint:

Answer:

0x99

14) What is the port number the shellcode binds to?

Hint:

  • reverse the shellcode?
  • use scdbg

Answer:

1957

15)The shellcode used a specific technique to determine its location in memory. What is the OS file being queried during this process?

Answer:

Kernel32.dll

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