Hands-On Ethical Hands-On Ethical Hacking and Network Hacking and Network

DefenseDefense

Chapter 8Chapter 8Microsoft Operating System VulnerabilitiesMicrosoft Operating System Vulnerabilities

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ObjectivesObjectives

Tools to assess Microsoft system Tools to assess Microsoft system vulnerabilitiesvulnerabilities

Describe the vulnerabilities of Microsoft Describe the vulnerabilities of Microsoft operating systems and servicesoperating systems and services

Techniques to harden Microsoft systems Techniques to harden Microsoft systems against common vulnerabilitiesagainst common vulnerabilities

Best practices for securing Microsoft Best practices for securing Microsoft systemssystems

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Tools to Identify Vulnerabilities Tools to Identify Vulnerabilities on Microsoft Systemson Microsoft Systems

Many tools are available for this taskMany tools are available for this task Using more than one tool is advisableUsing more than one tool is advisable

Using several tools help you pinpoint Using several tools help you pinpoint problems more accuratelyproblems more accurately

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Built-in Microsoft ToolsBuilt-in Microsoft Tools

Microsoft Baseline Security Analyzer Microsoft Baseline Security Analyzer (MBSA)(MBSA)WinfingerprintWinfingerprintHFNetChkHFNetChk

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Microsoft Baseline Security Microsoft Baseline Security Analyzer (MBSA)Analyzer (MBSA)

Effective tool that checks forEffective tool that checks for PatchesPatches Security updatesSecurity updates Configuration errorsConfiguration errors Blank or weak passwordsBlank or weak passwords OthersOthers

MBSA supports remote scanningMBSA supports remote scanning Associated product must be installed on Associated product must be installed on

scanned computerscanned computer

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MBSA ResultsMBSA Results

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88

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MBSA VersionsMBSA Versions

2.x for Win 2000 or later & Office XP or 2.x for Win 2000 or later & Office XP or laterlater

1.2.1 if you have older products 1.2.1 if you have older products

After installing, MBSA canAfter installing, MBSA can Scan the local machineScan the local machine Scan other computers remotelyScan other computers remotely Be scanned remotely over the Internet Be scanned remotely over the Internet

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HFNetChkHFNetChk

HFNetChk is part of MBSAHFNetChk is part of MBSA Available separately from Shavlik Available separately from Shavlik

TechnologiesTechnologies Can be used to control the scanning more Can be used to control the scanning more

precisely, from the command lineprecisely, from the command line

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WinfingerprintWinfingerprint

Administrative toolAdministrative tool

It can be used to scan network resourcesIt can be used to scan network resources

Exploits Windows null sessions Exploits Windows null sessions

DetectsDetects NetBIOS sharesNetBIOS shares Disk information and servicesDisk information and services Null sessionsNull sessions

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WinfingerprintWinfingerprint

Can findCan find OS detectionOS detection Service packs and hotfixesService packs and hotfixes Running ServicesRunning Services See Proj X6 for DetailsSee Proj X6 for Details

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Microsoft OS VulnerabilitiesMicrosoft OS Vulnerabilities

Microsoft integrates many of its products into Microsoft integrates many of its products into a single packagea single package Such as Internet Explorer and Windows OSSuch as Internet Explorer and Windows OS This creates many useful featuresThis creates many useful features It also creates vulnerabilities It also creates vulnerabilities

Security testers should search for Security testers should search for vulnerabilities onvulnerabilities on The OS they are testingThe OS they are testing Any application running on the serverAny application running on the server

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CVE (Common Vulnerabilities and CVE (Common Vulnerabilities and Exposures )Exposures )

A list of standardized names for A list of standardized names for vulnerabilitiesvulnerabilities

Makes it easier to share information about Makes it easier to share information about themthem cve.mitre.org (link Ch 8c)cve.mitre.org (link Ch 8c) Demonstration: Search Demonstration: Search

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Remote Procedure Call (RPC)Remote Procedure Call (RPC)

RPC is an interprocess communication RPC is an interprocess communication mechanismmechanism Allows a program running on one host to run code Allows a program running on one host to run code

on a remote hoston a remote host

Examples of worms that exploited RPCExamples of worms that exploited RPC MSBlast (LovSAN, Blaster)MSBlast (LovSAN, Blaster) NachiNachi

Use MBSA to detect if a computer is Use MBSA to detect if a computer is vulnerable to an RPC-related issuevulnerable to an RPC-related issue

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NetBIOSNetBIOS

Software loaded into memory Software loaded into memory Enables a computer program to interact with a Enables a computer program to interact with a

network resource or other devicenetwork resource or other device

NetBIOS is not a protocolNetBIOS is not a protocol NetBIOS is an interface to a network protocolNetBIOS is an interface to a network protocol It’s sometimes called a session-layer protocol, It’s sometimes called a session-layer protocol,

or a protocol suite (Links Ch 8d, 8e, 8f)or a protocol suite (Links Ch 8d, 8e, 8f)

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NetBEUINetBEUI

NetBIOS Extended User InterfaceNetBIOS Extended User Interface Fast, efficient network protocolFast, efficient network protocol Allows NetBIOS packets to be transmitted Allows NetBIOS packets to be transmitted

over TCP/IPover TCP/IP NBT is NetBIOS over TCPNBT is NetBIOS over TCP

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NetBIOS (continued)NetBIOS (continued)

Newer Microsoft OSs do not need Newer Microsoft OSs do not need NetBIOS to share resourcesNetBIOS to share resources NetBIOS is used for backward compatibilityNetBIOS is used for backward compatibility You can turn off NetBIOS for Windows 2000 You can turn off NetBIOS for Windows 2000

and later (links Ch 8g & 8h)and later (links Ch 8g & 8h)

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Server Message Block (SMB)Server Message Block (SMB)

Used by Windows 95, 98 and NT to share Used by Windows 95, 98 and NT to share filesfiles

Usually runs on top of NetBIOS, NetBEUI Usually runs on top of NetBIOS, NetBEUI or TCP/IPor TCP/IP

Hacking toolsHacking tools L0phtcrack’s SMB Packet Capture utilityL0phtcrack’s SMB Packet Capture utility SMBRelaySMBRelay Ettercap (see Project 23, Links Ch 8r & 8s)Ettercap (see Project 23, Links Ch 8r & 8s)

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Demonstration: ettercapDemonstration: ettercap

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Common Internet File System Common Internet File System (CIFS)(CIFS)

CIFS replaced SMB for Windows 2000, XP, CIFS replaced SMB for Windows 2000, XP, and Windows 2003 Serverand Windows 2003 Server SMB is still used for backward compatibilitySMB is still used for backward compatibility

CIFS is a remote file system protocol CIFS is a remote file system protocol Enables computers to share network resources Enables computers to share network resources

over the Internetover the Internet

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Common Internet File System Common Internet File System (CIFS) (continued)(CIFS) (continued)

Enhancements over SMBEnhancements over SMB Resource locking (if 2 people use the same Resource locking (if 2 people use the same

thing at once)thing at once) Support for fault toleranceSupport for fault tolerance Capability to run more efficiently over dial-upCapability to run more efficiently over dial-up Support for anonymous and authenticated Support for anonymous and authenticated

accessaccess

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Common Internet File System Common Internet File System (CIFS) (continued)(CIFS) (continued)

Server security methodsServer security methods Share-level securityShare-level security

A password assigned to a shared resourceA password assigned to a shared resource User-level securityUser-level security

An access control list assigned to a shared resourceAn access control list assigned to a shared resource

Users must be on the list to gain accessUsers must be on the list to gain access Passwords are stored in an encrypted form on the Passwords are stored in an encrypted form on the

serverserver

But CIFS is still vulnerable (see link Ch 8n)But CIFS is still vulnerable (see link Ch 8n) Don’t let NetBIOS traffic past the firewallDon’t let NetBIOS traffic past the firewall

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Understanding SambaUnderstanding Samba

Open-source implementation of CIFSOpen-source implementation of CIFS Created in 1992Created in 1992

Samba allows sharing resources over Samba allows sharing resources over multiple OSsmultiple OSs

Samba accessing Microsoft shares can Samba accessing Microsoft shares can make a network susceptible to attackmake a network susceptible to attack

Samba is used to “trick” Microsoft services Samba is used to “trick” Microsoft services into believing the *NIX resources are into believing the *NIX resources are Microsoft resourcesMicrosoft resources

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Samba is Built into UbuntuSamba is Built into Ubuntu

Click Places, Connect to ServerClick Places, Connect to Server Windows shares are marked with Windows shares are marked with SMBSMB

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Closing SMB PortsClosing SMB Ports

Best way to protect a network from SMB Best way to protect a network from SMB attacksattacks Routers should filter out portsRouters should filter out ports

137 to 139137 to 139

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Default InstallationsDefault Installations

Windows 9x, NT, and 2000 all start out Windows 9x, NT, and 2000 all start out with many services running and ports with many services running and ports openopen They are very insecure until you lock them They are very insecure until you lock them

downdown

Win XP, 2003, and Vista are much more Win XP, 2003, and Vista are much more secure by defaultsecure by default Services are blocked until you open themServices are blocked until you open them

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Passwords and AuthenticationPasswords and Authentication

A comprehensive password policy is A comprehensive password policy is criticalcritical Change password regularlyChange password regularly Require passwords length of at least six Require passwords length of at least six

characterscharacters Require complex passwordsRequire complex passwords Never write a password down or store it online Never write a password down or store it online

or on the local systemor on the local system Do not reveal a password over the phoneDo not reveal a password over the phone

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Passwords and AuthenticationPasswords and Authentication

Configure domain controllersConfigure domain controllers Enforce password age, length and complexityEnforce password age, length and complexity Account lockout thresholdAccount lockout threshold Account lockout durationAccount lockout duration

Start, Run, Start, Run, GPEDIT.MSCGPEDIT.MSC

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IIS (Internet Information Services)IIS (Internet Information Services)

IIS 5 and earlier installs with critical security IIS 5 and earlier installs with critical security vulnerabilitiesvulnerabilities Run IIS Lockdown Wizard (link Ch 8p)Run IIS Lockdown Wizard (link Ch 8p)

IIS 6.0 installs with a “secure by default” IIS 6.0 installs with a “secure by default” postureposture Configure only services that are neededConfigure only services that are needed Windows 2000 ships with IIS installed by defaultWindows 2000 ships with IIS installed by default Running MBSA can detect IIS running on your Running MBSA can detect IIS running on your

networknetwork

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IIS Buffer OverflowsIIS Buffer Overflows

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SQL ServerSQL Server

SQL vulnerabilities exploits areasSQL vulnerabilities exploits areas The SA account with a blank passwordThe SA account with a blank password SQL Server AgentSQL Server Agent Buffer overflowBuffer overflow Extended stored proceduresExtended stored procedures Default SQL port 1433Default SQL port 1433

Vulnerabilities related to SQL Server 7.0 Vulnerabilities related to SQL Server 7.0 and SQL Server 2000and SQL Server 2000

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The SA AccountThe SA Account

The SA account is the master account, The SA account is the master account, with full rightswith full rights

SQL Server 6.5 and 7 installations do not SQL Server 6.5 and 7 installations do not require setting a password for this accountrequire setting a password for this account

SQL Server 2000 supports mixed-mode SQL Server 2000 supports mixed-mode authenticationauthentication SA account is created with a blank passwordSA account is created with a blank password SA account cannot be disabledSA account cannot be disabled

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SQL Server AgentSQL Server Agent

Service mainly responsible forService mainly responsible for ReplicationReplication Running scheduled jobsRunning scheduled jobs Restarting the SQL serviceRestarting the SQL service

Authorized but unprivileged user can Authorized but unprivileged user can create scheduled jobs to be run by the create scheduled jobs to be run by the agentagent

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Buffer OverflowBuffer Overflow

Database Consistency Checker in SQL Database Consistency Checker in SQL Server 2000Server 2000 Contains commands with buffer overflowsContains commands with buffer overflows

SQL Server 7 and 2000 have functions SQL Server 7 and 2000 have functions that generate text messagesthat generate text messages They do not check that messages fit in the They do not check that messages fit in the

buffers supplied to hold thembuffers supplied to hold them

Format string vulnerability in the C runtime Format string vulnerability in the C runtime functionsfunctions

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Extended Stored ProceduresExtended Stored Procedures

Several of the extended stored procedures Several of the extended stored procedures fail to perform input validationfail to perform input validation They are susceptible to buffer overrunsThey are susceptible to buffer overruns

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Default SQL Port 1443Default SQL Port 1443

SQL Server is a Winsock applicationSQL Server is a Winsock application Communicates over TCP/IP using port 1443Communicates over TCP/IP using port 1443

Spida wormSpida worm Scans for systems listening on TCP port 1443Scans for systems listening on TCP port 1443 Once connected, attempts to use the Once connected, attempts to use the

xp_cmdshellxp_cmdshellEnables and sets a password for the Guest Enables and sets a password for the Guest accountaccount

Changing default port is not an easy taskChanging default port is not an easy task

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Best Practices for Hardening Best Practices for Hardening Microsoft SystemsMicrosoft Systems

Penetration testerPenetration tester Finds vulnerabilitiesFinds vulnerabilities

Security testerSecurity tester Finds vulnerabilitiesFinds vulnerabilities Gives recommendations for correcting found Gives recommendations for correcting found

vulnerabilitiesvulnerabilities

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Patching SystemsPatching Systems

The number-one way to keep your system The number-one way to keep your system securesecure Attacks take advantage of known vulnerabilitiesAttacks take advantage of known vulnerabilities Options for small networksOptions for small networks

Accessing Windows Update manuallyAccessing Windows Update manually

Automatic UpdatesAutomatic Updates This technique does not really ensure that all This technique does not really ensure that all

machines are patched at the same timemachines are patched at the same time Does not let you skip patches you don’t wantDoes not let you skip patches you don’t want

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Patching SystemsPatching Systems

Some patches cause problems, so they Some patches cause problems, so they should be tested firstshould be tested first

Options for patch management for large Options for patch management for large networksnetworks Systems Management Server (SMS)Systems Management Server (SMS) Software Update Service (SUS)Software Update Service (SUS)

Patches are pushed out from the network Patches are pushed out from the network server after they have been testedserver after they have been tested

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Antivirus SolutionsAntivirus Solutions

An antivirus solution is essentialAn antivirus solution is essential

For small networksFor small networks Desktop antivirus tool with automatic updatesDesktop antivirus tool with automatic updates

For large networksFor large networks Corporate-level solutionCorporate-level solution

An antivirus tool is almost useless if it is An antivirus tool is almost useless if it is not updated regularlynot updated regularly

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Enable Logging and Review Enable Logging and Review Logs RegularlyLogs Regularly

Important step for monitoring critical areasImportant step for monitoring critical areas PerformancePerformance Traffic patternsTraffic patterns Possible security breachesPossible security breaches

Logging can have negative impact on Logging can have negative impact on performanceperformance

Review logs regularly for signs of intrusion Review logs regularly for signs of intrusion or other problemsor other problems Use a log-monitoring toolUse a log-monitoring tool

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Disable Unused or Unneeded Disable Unused or Unneeded ServicesServices

Disable unneeded servicesDisable unneeded services

Delete unnecessary applications or scriptsDelete unnecessary applications or scripts

Unused applications or services are an Unused applications or services are an invitation for attacksinvitation for attacks

Requires careful planningRequires careful planning Close unused ports but maintain functionalityClose unused ports but maintain functionality

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Other Security Best PracticesOther Security Best Practices Use a firewall on each machine, and also a Use a firewall on each machine, and also a

firewall protecting the whole LAN from the firewall protecting the whole LAN from the InternetInternet

Delete unused scripts and sample Delete unused scripts and sample applicationsapplications

Delete default hidden sharesDelete default hidden shares Use different names and passwords for Use different names and passwords for

public interfacespublic interfaces

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Other Security Best PracticesOther Security Best Practices Be careful of default permissionsBe careful of default permissions

For example, new shares are readable by all users For example, new shares are readable by all users in Win XP in Win XP

Use available tools to assess system securityUse available tools to assess system securityLike MBSA, IIS Lockdown Wizard, etc.Like MBSA, IIS Lockdown Wizard, etc.

Disable the Guest accountDisable the Guest account Rename the default Administrator accountRename the default Administrator account Enforce a good password policyEnforce a good password policy Educate users about securityEducate users about security Keep informed about current threatsKeep informed about current threats