1. Onno W. Purbo Onno@indo.net.id
Cracking Techniques
Onno W. Purbo

2. Referensi http://www.rootshell.com
Front-line Information Security Team, “Techniques Adopted By 'System Crackers' When Attempting To Break Into Corporate or Sensitive Private Networks,” &

3. Referensi http://www.antionline.com/archives/documents/advanced/

4. Introduction

5. Just who is vulnerable anyway?
Financial institutions and banks
Internet service providers
Pharmaceutical companies
Government and defense agencies
Contractors to various goverment agencies
Multinational corporations

6. Profile of a typical 'system cracker'
Usually male, aged
To improve their cracking skills, or to use network resources for their own purposes.
Most are opportunists
Run scanners for system vulnerabilities.
Usually gain root access; then install a backdoor and patch the host from common remote vulnerabilities.

8. Networking methodologies adopted by many companies

9. Internet’s purposes .. The hosting of corporate webservers
and other global communications via. the internet
To give employees internet access

10. Network separation
Firewall
Application Proxies

12. Understanding vulnerabilities in such networked systems

13. Understanding vulnerabilities
External mailserver must have access to mailservers on the corporate network.
agressive-SNMP scanners & community string brute-force programs, turn router into bridge.

15. The attack

16. Techniques used to 'cloak' the attackers location
Bouncing through previously compromised hosts via. telnet or rsh.
Bouncing through windows hosts via. Wingates.
Bouncing through hosts using misconfigured proxies.

17. Network probing and information gathering
Using nslookup to perform 'ls <domain or network>' requests.
View the HTML on your webservers to identify any other hosts.
View the documents on your FTP servers.
Connect to your mailservers and perform 'expn <user>' requests.
Finger users on your external hosts.

18. Identifying trusted network components
a trusted network component is usually an administrators machine, or a server that is regarded as secure.
start out by checking the NFS export & access to critical directory /usr/bin, /etc and /home.
Exploit a machine using a CGI vulnerability, gain access to /etc/hosts.allow

19. Identifying vulnerable network components
Use Linux programs such as ADMhack, mscan, nmap and many smaller scanners.
binaries such as 'ps' and 'netstat' are trojaned to hide scanning processes.
If routers are present that are SNMP capable, the more advanced crackers will adopt agressive-SNMP scanning techniques to try and 'brute force‘ the public and private community strings of such devices.

20. Perform types of checks
A TCP portscan of a host.
A dump RPC services via. portmapper.
A listing of exports present via. nfsd.
A listing of shares via. samba / netbios.
Multiple finger to identify default accounts.
CGI vulnerability scanning.
Identification of vulnerable versions of server daemons, including Sendmail, IMAP, POP3, RPC status & RPC mountd.

21. Taking advantage of vulnerable components
Identify vulnerable network components  compromise the hosts.
Upon executing such a program remotely to exploit a vulnerable server daemon
Gain root access to your host.

22. Upon gain access to vulnerable components
'clean-up‘ operation of doctoring your hosts logs
'backdooring' service binaries.
place an .rhosts file in the /usr/bin to allow remote bin access to the host via rsh & csh

24. Abusing access & privileges

25. Downloading sensitive information
'bridge' between the internet - corporate network.
Abusing the trust with the external host.

26. Cracking other trusted hosts and networks
Install trojans & backdoors + remove logs.
Install sniffers on your hosts.

27. Installing sniffers Use 'ethernet sniffer' programs.
To 'sniff' data flowing across the internal network  a remote root compromise of an internal host.
To detect promiscuous network interfaces  the 'cpm'

28. Taking down networks rm -rf / &
'mission critical' routers & servers are always patched and secure.