Doomsday Preppers - HackMiami

Transcript

1. Doomsday Preppers: Fortifying Your Red Team Infrastructure
2. 1 Introduction
3. Whoami • Steve Borosh ◦ Penetration Tester / Red Teamer ◦ Blogger https://www.rvrsh3ll.net/ ◦ https://github.com/rvrsh3ll • Jeff Dimmock ◦ Penetration Tester / Red Teamer ◦ Blogger https://bluescreenofjeff.com/ ◦ https://github.com/bluscreenofjeff
4. Slides/Resources online bit.ly/RedTeamInfrastructure
5. Agenda ▪ Introduction ▪ “Standard” Infrastructure ▪ “Advanced” Infrastructure ▪ For The Blues: Tips and Tradecraft ▪ Questions
6. Purpose ▪ Infrastructure design ▫ Build a resilient infrastructure ▫ Stay hidden ▫ Separation of resources ▪ Secure the infrastructure ▫ Prevent “hack-back” ▫ Prevent data leakage ▪ Train both Blue and Red
7. Props to prior research ▪ blog.cobaltstrike.com - Raphael Mudge ▫ “A Vision for Distributed Red Team Operations” ▫ “Advanced Threat Tactics: Course and Notes” ▪ Cybersyndicates.com - Alex Rymdeko-Harvey ▫ “6 Red Team Infrastructure Tips”
8. 3 “Standard” Infrastructure
9. Design ▪ One (or few) hosts handle all functionality ▫ Payloads/C2/Phishing/etc ▪ Quick to deploy ▪ Simple hardening
10. Components ▪ Single-server C2 + SMTP ▪ Originates all attacks ▪ Default traffic profiles ▪ Open to entire Internet
11. Use Cases ▪ Tests w/o active incident response ▪ Fully whitebox ▪ Functional testing ▫ Click tracking ▫ Egress testing
12. Attacker Router/Firewall C2/SMTP Server Router/Firewall Victim
13. Weaknesses ▪ Hosted payloads are easily enumerated by defenders ▪ C2 may be easily blocked by IP, netblock, or domain name ▪ No redundancy in case of outages ▪ Susceptible to Internet-wide probing or exploitation
20. 5 “Advanced” Infrastructure
22. Design ▪ Based on “Infrastructure for Ongoing Red Team Operations” by Raphael Mudge ▪ Segregate assets based on function, minimize overlap ▪ Place redirectors in front of every host
23. Design ▪ Document the setup ▫ Know what points where ▪ Split hosts amongst providers ▫ (Pay attention to terms of service!) ▪ Forward all logs to central server via rsyslog
24. Components ▪ Four teamservers ▫ Phishing & payloads ▫ Long-term DNS C2 ▫ Short-term DNS C2 ▫ Short-term HTTP C2 ▪ Four redirectors (VPS hosts) ▫ Two for DNS C2 via socat/iptables ▫ HTTP C2 via Apache ▫ HTTP payloads via Apache ▪ SMTP server (VPS host) ▪ Four domains
26. Domains ▪ expireddomains.net ▫ Old first registered age ▫ High SimilarWeb score ▫ High number of backlinks ▪ Register pre-used domains ▪ Register domains in same category ▪ Finance/Healthcare usually have firewall exceptions for SSL
27. Domains
28. Domains
29. Domains ▪ Check categorization ▫ Bluecoat ▫ McAfee (TrustedSource) ▫ Fortiguard ▪ Senderbase Score ▫ http://www.senderbase.org/ ▪ Check blacklists (web and email) ▫ http://multirbl.valli.org/
30. Domains
31. Domains
32. Domains
33. SMTP ▪ Use “redirector” for sending ▪ Remove previous server headers ▪ Catch-all address to receive bounce-backs or responses ▪ Use third-party SMTP servers ▫ Read the TOS first!
34. Apache mod_rewrite ▪ Redirect unwanted requests ▫ Invalid URIs ▫ IR useragents ▫ Blacklisted IPs ▪ OS-specific payload delivery ▪ Payload extension hiding ▪ Filter non-C2 requests to C2 domains
36. Mobile Redirection Apache mod_rewrite
37. Invalid URI Redirection Apache mod_rewrite
38. Apache mod_rewrite OS-Specific Payloads
39. Apache mod_rewrite
40. Apache mod_rewrite
41. DNS ▪ socat vs. iptables ▫ https://github.com/bluscreenofjeff/Red- Team-Infrastructure-Wiki#dns ▪ Modify query results in profile ▫ Typical default of 0.0.0.0 ▫ Nslookup = google,opendns ▪ Modify DNS request lengths ▫ Max domain name, 253 text characters ▫ MRZGS3TLEBWW64TFEBXXM.dns.example.com
42. DNS Redirection Socat http://www.rvrsh3ll.net/blog/offensive/redir ecting-cobalt-strike-dns-beacons/ IPTables ▪ Forward UDP port 53 to teamserver from redirector
43. DNS Redirection
44. DNS Redirection
45. DNS Redirection
46. NAT’d DNS Redirection Cobalt Strike (192.168.20.10) SOCAT & SSH Main Redirector (104.236.x.x) SOCAT Volatile Redirector (45.63.y.y) IPTables https://gist.github.com/pcting/1041387
47. Modify Your C2 Channels! ▪ Don’t use defaults ▪ Use a different profile for each c2 channel ▪ Blend your profiles into your target environment
48. Modified C2 Signatures ▪ Changes how C2 looks on the wire ▪ Impersonate adversary or internal applications ▪ Malleable C2 -> Cobalt Strike ▪ Communication Profile -> Empire ▪ Use custom profiles on every server!
49. Malleable C2 Example (Amazon Traffic) https://raw.githubusercontent.com/rsmudge/Malleable-C2-Profiles/master/normal/pandora.profile
50. Modified C2 Signatures
51. Modified C2 Signatures
52. Modified C2 Signatures
53. Domain Fronting
54. Domain Fronting ▪ https://www.bamsoftware.com/paper s/fronting/ ▪ Utilize high-trust domains ▫ Cloudfront ▫ AWS ▫ Google ▪ Implementation varies per provider
56. Domain Fronting (cont.)
57. Domain Fronting (cont.) ▪ Resources “High-reputation Redirectors and Domain Fronting” -Raphael Mudge “Domain Fronting via Cloudfront Alternate Domains” -Vincent Yiu “Escape and Evasion Egressing Restricted Networks” -Chris Patten and Tom Steele
58. Finding Frontable Domains ▪ Searchable by CNAME ▫ Google ‘CNAME “*.cloudfront.net”’ ▪ Bruteforce/find subdomains ▫ Can search alexa top x sites ▫ Search by domain ▫ https://github.com/rvrsh3ll/FindFrontab leDomains
60. Watching the watchers ▪ ‘Pre-phish’ with a weak phish to fingerprint response ▫ Easy-to-spot, but not Nigerian Prince ▫ Use completely different infrastructure ▫ Perform far in advance ▫ Skype Pre-Phish: https://www.youtube.com/watch?v=oTyLdAU jw30 ▪ WATCH ALL LOGS ▫ Look for CURL/WGET/Python requests ▫ Geolocate IPs ▫ ID appliances ▫ ID incident response actions
61. Watching the watchers ▪ Monitor domain/IP categorization/blacklisting ▪ Monitor emails, if possible ▫ Compromised accounts ▫ Bouncebacks ▪ Roll infrastructure as needed
62. Securing the Infrastructure ▪ Attackers can be attacked too! ▫ Metasploit* ▫ Empire** ▫ Cobalt Strike*** ▪ RCE on unprotected attack infrastructure *https://github.com/justinsteven/advisories/blob/master/2016_metasploit_rce_static_key_deserialization.md *https://github.com/justinsteven/advisories/blob/master/2017_metasploit_meterpreter_dir_traversal_bugs.md **http://www.harmj0y.net/blog/empire/empire-fails/ ***http://blog.cobaltstrike.com/2016/10/03/cobalt-strike-3-5-1-important-security-update/
63. Securing the Teamserver ▪ Chattr cron directories ▪ iptables ▫ Restrict resources to only needed IPs ▪ Lock down SSH ▫ PKI auth only ▫ Limited user rights
64. Securing the Teamserver (cont.) ▪ Block non-target country IPs ▪ Keep your C2 updated!
65. 7 For the Blues
67. Hunting C2 Infrastructure ▪ Default requests ▫ Notable lack of headers ▫ Lack of proper HTTP response codes ▪ Static Content ▫ “It Works!” responses ▪ Reference ▫ http://www.chokepoint.net/2017/04/hunti ng-red-team-empire-c2.html ▫ http://www.chokepoint.net/2017/04/hunti ng-red-team-meterpreter-c2.html
68. Default Empire Response
69. Shodan Search For Empire http://securesql.info/hacks/2017/4/5/fall-of-an-empire
70. Identifying malicious DNS traffic ▪ Request length ▪ Same domain with many subdomains ▫ Entropy in subdomains ▪ KDJSOISJFSLKJSOIFJ.example.com ▪ Subdomain.example.com ▪ DNS Server resolves to 0.0.0.0 or something funky
71. Identifying other malicious traffic ▪ SSL Certs ▫ Let’s Encrypt Certs ▫ Self-Signed ▪ Consistent URL patterns ▫ /admin.php etc.. ▫ Repeated intervals with Bro ▪ Research common C2 platforms ▫ (low hanging fruit for defenders) ▫ Stagers are easy to spot
72. Identifying Malicious traffic (cont.) ▪ Analyze network captures ▫ Beacon intervals (jitter) ▫ Filter out known-good ▪ VPS address ranges
73. VPS Lookup
74. Thanks! ANY QUESTIONS? You can contact us at: @424f424f (Steve Borosh) @bluscreenofjeff (Jeff Dimmock) http://www.rvrsh3ll.net https://www.bluescreenofjeff.com