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Cracking Techniques

Cracking Techniques. Onno W. Purbo Onno@indo.net.id. 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,” fist@ns2.co.uk & http://www.ns2.co.uk. Referensi.

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Cracking Techniques

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

  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,” fist@ns2.co.uk & http://www.ns2.co.uk

  3. Referensi • http://www.antionline.com/archives/documents/advanced/ • http://www.rootshell.com/beta/documentation.html • http://seclab.cs.ucdavis.edu/papers.html • http://rhino9.ml.org/textware/

  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 16-25. • 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.

  7. Networking methodologies adopted by many companies

  8. Internet’s purposes .. • The hosting of corporate webservers • E-mail and other global communications via. the internet • To give employees internet access

  9. Network separation • Firewall • Application Proxies

  10. Understanding vulnerabilities in such networked systems

  11. 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.

  12. The attack

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Abusing access & privileges

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

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

  23. 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' http://www.cert.org/ftp/tools/cpm/

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

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