Exploiting hardware management subsystems

Transcription

1 Exploiting hardware management subsystems "ilo, ilo, it s off to work we go!" CRESTCon 2014 Simon Clow 19/03/2014

2 Overview Introduction to Hardware Management Systems (HMS) Identification of HMS Whilst Testing Tools of the Trade Penetration Testing Initial Exploitation Secondary Actions Demonstrations Demo Part 1: Basic skills Demo Part 2: a 15 year-old 0-Day?

3 Hardware Management Systems Why Should We Know or Care about HMS? Modern computing systems implement a variety of remotely accessible, instrumented management interfaces. Not all of them are obvious! As professional penetration testers it is important to understand the capabilities of such interfaces Otherwise we cannot exploit them! How do we identify the management interfaces if we are not aware of them? How do we advise customers how to protect the management interfaces if we are unaware of the security considerations?

4 Introduction To Common Technologies

5 Common Technologies Baseband Management Controllers Service Controllers (SC s) Intel AMT Active Management Technology vpro - KMS Computrace IP Management Interface (IPMI)

6 Common Technologies (Cont..) Lights out Management (LOM) Dell DRAC HP ilo Oracle (Sun) ilom, alom and serial LOM Supermicro IPMI An IPMI 2.0 reference client? Various Others

7 Baseband Management Controller (BMC)

8 BMC Baseboard Management Controller A dedicated computer that can manage the host system Monitors the physical state of a device Highly Instrumented Temperature Power State Network Connectivity Case Intrusion Fan State / Speed BMC s communicate with the administrator through an independent connection or API.

9 BMC (Cont.) BMC Firmware Rarely Updated At least not as part of the normal patch update cycle BMC Upgrades may improve host performance BMC has direct interfaces to key (security) related component's: DMA Direct Memory Access I2C Bus Controllers BIOS / UEFI Configuration Raw Device Access

10 Service Controllers

11 Service Controller Service Controller (SC) Many BMC s implement a service controller (but not all!) Often termed service console or service processor BMC may require dedicated authentication SC s typically provide a shell from which the BMC can be managed. However, not all SC s are accessible Laptops often have SC, generally integrated into ACPI

12 Service Controller (Cont.) Service Controller (SC) Each Individual SC has their access method: Serial (RS-232 or RJ45) Telnet SSH Proprietary API

13 Service Controller (Cont.) Service Controller (SC) Monitors the instrumentation in BMC and then schedules actions E.g. CPU Watchdog, restart host if CPU hung Works in conjunction with BMC to tune the host. ACPI is often a SC function CPU Tuning when on battery power

14 Intel Advanced Management Technology (AMT)

15 AMT Advanced Management Technology Intel Specific technologies implemented into both: Processor *and* Chipset Uses IPv6 Broker and SSL to Connect to Management Center Allows BIOS reconfiguration Virtual Media Support Allows OS Re-installation Think of it as RealVNC integrated into BIOS..

16 AMT (Cont.) Advanced Management Technology Remote KMS vpro Intel Management Command Toolkit (MCT) Optional Web Interface Delivers custom VNC Client Older Versions (Pre 2013 / AMT 6.0) Require Authentication (password only) to access Must be exactly 8 characters! Unless it is one of the defaults (username is admin): admin P@ssw0rd

17 AMT (Cont.) Newer Versions (2013+ / AMT 7.0 +) Connects back to Intel vpro Platform Solution Manager PKI based authentication Boundary-less connection (via IPv6 Broker) Able to remotely execute AMT plugins Privileged (System) level code execution Remote (graphical) control Is this the Ultimate Red-Teaming tool?

18 Computrace

19 Computrace Absolute Software, Computrace Sales Pitch. Computrace is the only endpoint security solution in the world that can remain installed on computers, laptops, tablets, smartphones, and other devices regardless of user or location. If the software agent is removed (accidentally or on purpose) it will automatically reinstall. Very Widely Deployed Supported by Well Known Manufacturers

20 Computrace Context reviewed in 2010 as a customer research project: Analysis: Persistent even with OS Rebuild! Can Exfiltrate Data Supports Command Execution 3 rd Rate CnC Conclusion Looks and behaves like Malware Recommendation: Customer not to enable it, and reject systems shipped with it enabled.

21 Computrace Kaspersky Labs (Feb 2014): Computrace uses many tricks popular among malicious software. For example, it uses anti-debugging and anti-reverse engineering techniques, injects memory into other processes and keeps configuration files encrypted. The network protocol used by the Computrace Small Agent provides basic features for remote code execution. The protocol does not require the use of any encryption or authentication of the remote server, opening up avenues of attack. mputrace_revisited

22 IP Management Interface (IPMI)

23 IPMI Intelligent Platform Management Interface (IPMI) A collection of specifications that define communication protocols for: Access to Local System Bus (SMBus/BMC/I2C) Network Communication (LAN / LANPLUS )

24 IPMI

25 IPMI Intelligent Platform Management Interface (IPMI) A collection of specifications that define communication protocols for: Access to Local System Bus (SMBus/BMC/I2C) Network Communication (LAN / LANPLUS ) Two widely implemented variants: 1.5 Up to onwards

26 IPMI IPMI 1.5 No Encryption At least not within standard Implementations No Console redirection SOL Serial Over LAN Text only console access (*NIX) BIOS admin

27 IPMI IPMI 2.0 Introduced Encryption ish more later Provided Authentication Framework Stronger User Privilege Separation Challenge / Response Hashes can be cracked Passwords stored in clear text explore SC! Console redirection Virtual Media

28 IPMI IPMI Networking IPMI can be configured to *share* first NIC on motherboard SC/BMC will respond to IPMI requests to *hosts* IP address. Host will send UDP port unreachable client apps must be able to handle that. Will often fallback to first NIC if dedicated LOM card removed Heat Causes Motherboard Expansion - Cards walking out Over eager administrators removing LOM as they know about IPMI security issues

29 Lights Out Management (LOM)

30 Lights Out Management Intended to Provide Out of Band Management Historically present on high end kit: Solaris LOM Port Serial over RJ45 Solaris [a i]lom HTTP / SSH / IPMI +++ HP ilo Dell DRAC (and now idrac) And pretty much every other enterprise manufacturer

31 Lights Out Management Lights Out Management Generally provide web management interface Predominantly using ActiveX / Java plugin s and browser detection. Primary role is usually to provide zero installation client Client is used to perform the actual management Often based on VNC Advanced Functions Client to enable the use of Virtual Media Redirected Consoles Provides GUI access to OS and BIOS

32 Penetration Testing

33 Penetration Testing The Bare Minimum What Should we be able to do? Identify common Hardware Management Subsystems Identify security defects within the deployed subsystem Perform basic "false negative" detection Exploit common security defects Post exploitation activities

34 Penetration Testing How To: Identify common Hardware Management Subsystems Look for the management services: IPMI (UDP 623) SSH (TCP 22) Telnet (TCP 23) HTTP & HTTPS (TCP 80 / TCP 443)

35 Penetration Testing Identify common Hardware Management Subsystems Perform basic "false negative" detection Be aware of NIC sharing! Connect to services, don t just portscan! Remember OS may report port s closed and SC/BMC still respond. Remember Nessus is Imperfect! Dell idrac rarely reports Cipher 0 despite being vulnerable. When it is reported, the firmware is very OLD!

36 Penetration Testing How to: Identify security defects within the deployed subsystem Check for Cipher 0 Check whether HMS support the extraction of password hashes Attempt Anonymous Access (IPMI + Web Service force browsing) Recent Test: Management Application Controlled backend SC s App required current JSESSIONID + current CLIENT-ATH value. CLIENT-ATH provided by connecting to port 8123 (?) Could replay add user SOAP function with valid (unauthenticated) JSESSIONID and CLIENT-ATH to add new admin user - *or* Use an unauthenticated file upload function in order to upload arbitrary /root/.ssh/authorized_keys

37 Penetration Testing Exploiting common security defects Extract and crack hashes (Metasploit / John the Ripper) Use default credentials (lots of them!) If vulnerable to Cipher 0 just reconfigure

38 Penetration Testing Post exploitation activities Hardware is compromised! Direct Memory Access / Memory Corruption Dependent on I2C Dependent on LOM functionality Reboot into alternate OS? Credentials harvesting On Domain Controller - OphCrack live via virtual media Deploy tools MetSVC replacing Anti-Virus service binary on Exchange

39 Tools of the Trade

40 Tools of the Trade Tools to Access LOM s An Older browser (seriously!) Java Run Time (JNLP/Java 1.4 plugin s) ActiveX May need to degrade your browsers security to get it working! Internet Explorer 10/11 very rarely supported Telnet / SSH My experience is more often than not it will be telnet (!)

41 Tools of the Trade IPMI Client Tools ipmitool bmc-config Supermicro Java implementation Limitations: Library miss-matches can cause false negatives Libgcrypt Libcrypto OpenSSL Tools are generally released just for *NIX systems

42 Tools of the Trade Status of IPMI Support in Common Toolkits Kali Broken at various times in 1.04 / 1.05 Working (as of 13/03/2014) in 1.06 CentOS / RHEL / Scientific Linux Native ipmitool compiled so as to not support Cipher 0 due to it being a security vulnerability. Debian / Ubuntu ipmitool / bmc-config in most repo s is currently broken. RMCP connections silently fail (False negative).

43 Demo Time!

44 IPMI Demo - Identification IPMI UDP 623 (Alert Standard Format) In the case of IPMI on a Shared NIC? OS Believes Port Closed, port scan fails BMC responds to *valid* IPMI queries, not port scans! Wireshark will allow you to see both OS and HMS responding.

45 IPMI Demo - Identification IPMI UDP 623 (Alert Standard Format) In the case of IPMI on a Shared NIC? OS Believes Port Closed, port scan fails BMC responds to *valid* IPMI queries, not port scans! Wireshark will allow you to see both OS and HMS responding.

46 IPMI Demo Cipher 0 IPMI 2.0 Implemented Cryptography We all know cryptography is hard (!) Therefore the standard mandates first Cipher (0) to be null crypto (clear text) Obviously null crypto is bad for sending credentials on the wire Therefore we should disable authentication if using Cipher 0 And implicitly trust the username supplied by the client (?) Really, it is required to be compliant with the RFC! No it wasn t an April 1 st RFC (12/02/2004) but it probably should have been!

47 IPMI Demo BMC-Config BMC-Config Not *technically* IPMI but does support LANPLUS for connections (like IPMI 2.0 it also provides Cipher 0) LANPLUS implemented as driver, LAN_2_0 Ignore documents that show LAN_2.0 BMC-Config checkout Get the controller to show you the syntax to reconfigure it!

48 IPMI Demo BMC-Config BMC-Config - reconfigure Easiest attack to do, simply use a config file (Context.ipmi) Can do / undo more easily

49 IPMI Demo BMC-Config

50 IPMI Demo BMC-Config BMC-Config - reconfigure Easiest attack to do, simply use a config file (Context.ipmi) Can do / undo more easily Make sure you view checkout first and get Manufacturer specific configuration options, these are not equivalent: None No Access NoAccess No_Access

51 Dell idrac - Primer idrac Comes in various flavours : Enterprise Express aka Lite version A combination of SC + BMC + IPMI on dedicated interface Administrative GUI (Web Based) Java / Active X plugin (depending on browser)

52 IPMI Demo idrac IPMI!= idrac Enterprise IPMI Users are not the same as idrac users. idrac Enterprise add an additional authentication layer (idrac), configurable locally but not remotely! Newly added context user wont work on Enterprise idrac This technique will work on pretty much everything else though. But don t worry there is a solution for idrac!

53 IPMI Demo idrac IPMI can configure idrac root user We can use IPMI to set the root users password: Easy to confirm our changes: Either using IPMI Or logon to idrac web console

54 IPMI Demo idrac? Do we actually need idrac? idrac Enterprise provides a handy pre-packaged client, its inbrowser: Java ActiveX However we can use IPMI to perform a lot of the functions of idrac Supermicro Java Client

55 IPMI Demo Metasploit Surely we can use Metasploit? Yes: Metasploit has re-implemented IPMI inside a ruby library, code ported from xcat. Extreme Cluster Administration Toolkit Metasploit library is currently limited to providing read only access: Identification of users IPMI user list Cracking of passwords

56 Freebies! IPMI Cygwin compiled ipmitool and bmc-config No worries about library linking issues. (Unset PATH && LD_LIBRARY_PATH) Excellent for Pivoting through Windows boxes; take one and then sploit the others through shared MGMT VLAN s Intel Management Command Toolkit (AMT)

57 #0Day or #0ldsk00l You Decide!

58 #0Day or #0ldsk00l? Is this an #0day or is it just #0ldsk00l? Assuming Oracle (Sun) SPARC Systems: [a i]lom -> Cipher 0 to seize control of LOM Can break from LOM into Service Controller Service Controller -> console and #. access to OpenBoot PROM OpenBoot PROM -> break command OBP Written in Forth, can extend without recompiling Direct Memory Modification Hacking in Forth - Phrack Magazine - 7 Aug 1998

59 #0Day or #0ldsk00l? Seizing [a i]lom Cipher 0 to seize control of LOM user account ipmitool -H v -I lanplus -C0 -U admin - P BadPass user list ipmitool -H v -I lanplus -C0 -U admin - P BadPass user set password 3 abc123 Verify Control ipmitool -H v -I lanplus -U admin - P abc123 user list telnet l admin ssh admin@

60 #0Day or #0ldsk00l? Seizing [a i]lom (cont.) *OR* Try Default Credentials ALOM: admin + last 8 characters of serial number ipmitool -H v -I lanplus -C0 -U admin -P BadPass fru print ILOM: root / changeme *OR* Just use Cipher 0 to bypass authentication IPMI Support in early ALOM is very limited.

61 #0Day or #0ldsk00l? Migration to Service Controller From Sun (Oracle) documents we know we can break from LOM into Service Controller console -> Into SC #. -> Return to LOM Alternatively we can bypass the migration step and go straight to SC using IPMI: ipmitool -H v -I lanplus -C0 -U admin - P BadPass sunoem cli

62 #0Day or #0ldsk00l? Migrating from SC to OpenBoot PROM (OBP) break -y command halts Solaris OS (and doesn t prompt!) console -f drops us to the running OS console but actually into OBP if OS is halted -f forces a read-write connection (disconnects existing session) OBP Written in Forth We can extend functionality without recompiling, including direct memory access go command resumes execution of Solaris OS

63 #0Day or #0ldsk00l? Direct Memory Modification Hacking in Forth - Phrack Magazine - 7 Aug 1998 Assumed 32bit Solaris structures and the ability to extract base memory from userland Solaris 10(+) 64Bit OS / 32Bit Userland (by default) 64Bit base memory addresses to large to express as 32Bit numbers; Therefore OS masks base address from 32Bit processes However, we can get base memory address of processes if we explicitly use 64Bit calls.

64 #0Day or #0ldsk00l? Direct Memory Modification (cont.) Credentials structure has changed in Solaris 10(+) But by inspecting OpenSolaris we can find the offset for both Effective UID (EUID) and Real UID (RUID) Credential structure no longer Basemem + 0x18 - Now it is Basemem + 0x20 -

65 #0Day or #0ldsk00l? Sploit Time! This assumes you have already pwned [a i]lom via IPMI or credential guessing using your new skillz. We will be using telnet to connect to SC (dirty) IP Addresses Used: SSH Session to Solaris server (as simon low privileged) Telnet session to ALOM on SunFire v240

66 #0Day or #0ldsk00l? Mitigation: Follow Oracle s best practice security advice: LOM as a dedicated Management Network Use Firewall Change default credentials Enable OpenBoot PROM Security Mode (Advice from 1994!) It is Context s experience that whilst OS security is considered, HMS security as a wider concept is not! Solaris system was chosen purely to demonstrate HMS access is equivalent to physical access (e.g. at the console) It provides a very visual demonstration as to the impact of direct memory modification!

67 Any Questions?