AIXpert - AIX Security expert

AIX 6.1 Security Expert
May 2011
AIXpert

© Copyright 2010 by Mt Xia Inc, All rights reserved. mxase-2
AIX V6.1 Security Expert
A new capability of AIX V6.1 that allows privileged
administration tasks to be delegated to non-privileged users
Access to system resources are associated with roles that are
assigned to non-privileged users
Many roles are predefined which can reduce the effort of
implementing RBAC
Roles can also be associated with programs

Authorizations
– Mechanism to grant access to commands or certain
functionality.
– Context aware.
Roles
– A container for authorizations that can be assigned to a
user.
Privileges
– Process attribute that allows a process to bypass a
security restriction.
– Not context aware.
Authorizations vs. Privileges
– Auths exist only outside of kernel, Privs only inside
– Auths enable access to commands, Privs enable execution
of single functions
– e.g. "run mkuser" vs. "PV_DAC_W"
Role Based Access Control (RBAC)

Role Based Access Control (RBAC)
Separation of duties through roles:
Main pre-defined AIX Roles:
– ISSO Information Systems Security Officer
• Establishes and maintains security policy
– SA System Administrator
• Creates user accounts, groups, etc.
• Installs software packages
– SO System Operator
• Archives file system
• Manages line printer
• Shuts down system
– Additional pre-defined AIX Roles:
• AccountAdmin, BackupRestore, DomainAdmin,
FSAdmin, SecPolicy, SysBoot, SysConfig.

A centralized security management tool that can control over 300
security settings from a single console.
Administrators can start from a “Low”, “Medium”, “High” or
“Sarbanes-Oxley” security template and customize settings to
meet business requirements.
Security settings can be exported and imported as a security
profile to multiple systems.
On AIX V6.1, security profiles can be stored in an LDAP directory
for ease of distribution.
AIX Security Expert was first included in AIX V5.3 TL5.
AIX V6.1 Security Expert: How it can help?

AIX 6 introduces three new security installation options
– Trusted AIX (MLS)
– Multi-Level Security
– LSPP/EAL4+
– Labeled Security Protection Profile and Evaluation
Assurance Level 4+
– SbD - Secure by Default
SbD is new default security option
– Installs a minimal set of software
– Deletes components that use weak authorization
(bos.net.tcp.client|server) and runs AIX Security Expert to
apply hardening for level "high"
– Additional software installed on as-needed basis
Secure by Default (SbD)

"Bottom Up" Approach
– Reverses traditional "Top Down" approach of full install
followed by hardening
Thorough planning strongly suggested
– Can all applications' requisites be fulfilled by this install
template?
Secure by Default (SbD) (Continued)

Based on OpenSSL
– needed to setup and handle keys and certificates
ftp and ftpd are secured using TLS protocol
– Command channel and data channel are encrypted
Nice add-on to OpenSSH's 'scp' and 'sftp'
– e.g. data exchange with legacy systems not offering SSH
Client usage is 'ftp -s …'
– TLS stuff is configured in user’s ~/.ftpcnt file
Server usage is implicit
– TLS stuff is configured in /etc/ftpd.cnf
Secure FTP

Automatically encrypt data in a JFS2 filesystem
Data can be protected from access by privileged users
Backup in encrypted or clear formats
Automated key management
– key store open on login, integrated into AIX security
authentication
Each file encrypted with a unique key
No keys stored in clear in kernel memory
A variety of AES, and RSA cryptography keys supported
AIX V6.1 Encrypting Filesystem

Embedded in JFS2, not stacked, for performance and reliability
– all JFS2 operations can be performed with an EFS
• mounting and unmounting, increasing and
decreasing size, defragmenting, removing, …
• but no NFS or GPFS support
– In stacked FSs, data may be lost through strong encryption
when crypto meta data write and data write are out of sync
Each file is encrypted with a separate key (stored in its Eas)
AIX V6.1 Encrypting Filesystem

Encryption/Decryption happens in memory, not on storage
– hence no DIO/CIO
User keystore gets opened by login password or separate pw
– login pw is distinct from keystore pw
– holds user's private and public key (asymmetric encryption,
RSA)
– public key is used to access shared secret for file
en/decryption (symmetric encryption, AES)
– hybrid approach for the sake of performance (e.g. like TLS)
AIX V6.1 Encrypting Filesystem (Continued)

Prereqs
– CryptoLite in C (CLiC) library and kernel extension must be
installed and loaded
– Enhanced RBAC must be enabled (default in AIX6)
– EFS must be explicity enabled (can be done at any time
using 'efsenable')
New and existing FShttp://www.tecmint.com/linux-server-hardening-
security-tips/s can be encrypted
– smitty crfs -> "Enable EFS? [yes]"
– 'crfs' or 'chfs' along with "-a efs=yes"
– not to be applied on "/", /usr, /var and /opt since keystore
can't be opened during boot
– but that's OK, since EFS' main focus is on
protectinguser/application data
– encrypted files can be identified by 'ls -U'
Encrypted File System (EFS)

# ls -U file*
-rw-r--r--- 1 root system 0 May 14 13:22 file1
-rw-r--r--e 1 root system 0 May 14 13:22 file2
User key management is provided with 'efskeymgr' command
Performance penalty is said to be low*)
– best practice: use it selectively where needed, not
everywhere e.g. on sensitive filesystems only, selected DB
columns, etc.

Two keystore protection modes
– Root Admin Mode
• Pro: Root can reset user and group key store
access passwords
• Con: Root might be able to gain access to a user's
key store and encrypted files
– Root Guard Mode
• Pro: Root cannot reset user and group key store
access passwords
• Con: Root cannot gain access to a user's key store
and encrypted files, even when necessary!
EFS backup Best Practices
– Backup raw encrypted form
– Backup the file owner's keystore
– The file owner's keystore password must also be "saved" or
files must be re-encrypted in a timely manner when keystore
pw changes

A new web based management tool that provides easy access to
common system administration tasks
Administrators can access Systems Management Interface Tool
(SMIT) menus from a browser
Graphical user interface is fast and consistent with IBM Systems
Director look and feel
All necessary components for the Console are included in AIX
The Distributed Command Execution Manager (DCEM) feature of the
Console allows an administrative task to run on multiple systems at
once
AIX V6.1 Systems Director Console for AIX

Remote AIX management from a web browser
– Verify Fileset installation
# lslpp -h sysmgt.pconsole.rte
Use SRC to control the director console
# lssrc -s pconsole
Subsystem Group PID Status
pconsole pconsole 319644 active
Stop and start with startsrc and stopsrc
Access from your browser
– http://HostName:5335/ibm/console
View and save commands like smit
Config file
– /pconsole/lwi/conf/overrides/config.properties
IBM Systems Director Console

From global LPAR use the -@ flag to designate WPAR
# ps -ef -@ ec08
WPAR UID PID PPID C STIME TTY TIME CMD
ec08 root 217128 389182 0 15:00:58 - 0:00 /usr/sbin/rsct/b
ec08 root 266398 389182 0 15:00:21 - 0:00 /usr/sbin/rsct/b
ec08 root 278634 389182 0 15:00:20 - 0:00 /usr/sbin/rpc.lo
ec08 root 290942 389182 0 15:00:18 - 0:00 /usr/sbin/biod 6
WPAR command support

From WPAR use normal commands
# ps -ef
UID PID PPID C STIME TTY TIME CMD
root 217128 389182 0 15:00:58 - 0:00 /usr/sbin/rsct/bin/IBM.Sensor
root 266398 389182 0 15:00:21 - 0:00 /usr/sbin/rsct/bin/rmcd -a IB
root 278634 389182 0 15:00:20 - 0:00 /usr/sbin/rpc.lockd -d 0
root 290942 389182 0 15:00:18 - 0:00 /usr/sbin/biod 6
root 1 0 0 15:00:04 - 0:00 /etc/init

Some commands are not supported from WPAR
# netstat -rn
Routing tables
Destination Gateway Flags Refs Use If Exp Groups
netstat : Permission error, unable to continue.

Network adapters are alias on global partition
# ifconfig en0
en0:
flags=1e080863,480<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLE
X,...
inet 9.19.51.153 netmask 0xffffff00 broadcast 9.19.51.255
inet 9.19.51.154 netmask 0xffffff00 broadcast 9.19.51.255
tcp_sendspace 262144 tcp_recvspace 262144 rfc1323 1

AIX Security Expert
– AIX 5.3 TL5
Secure By Default
– AIX 6.1
File Permission Manager
– AIX 5.2, 5.3, 6.1
Role-base Access Cntl
– AIX 6.1
Encrypted File System
– AIX 6.1
Trusted Execution
– AIX 6.1
Trusted AIX
– AIX 6.1
AIX Security Feature Release Schedule

Long Passphrase
– AIX 5.2, 5.3, 6.1
Configurable Password Algorithms
– AIX 5.3, 6.1
Enhancements for LDAP R2 Support
– AIX 5.3, TL 6
AIX Security Feature Release Schedule

Support for extended base DN format
Support for multiple base DN definitions
AIX LDAP Client support against Microsoft Active Directory
LDAP

Enable AIX client to use Active Directory (AD) LDAP
– Support AD similar to any RFC 2307 compliant LDAP
server.
AD users must be UNIX enabled
AD must have UNIX schema support installed
Users can be managed from the AIX LDAP client, but the
system administrator should create users in AD.
Transparent to administrators and users
– Hide all implementation details
– Use 'mksecldap'to configure AIX client to operate with AD
AIX LDAP Client support against Microsoft Active
Directory

Fileset: bos.net.ipsec
Firewall
– Packet filtering
– Stateful inspection filtering
NAT Support
Virtual Private Network
– FTP
– IKE/ISAKMP
Port Scan Protection
– SSH
Pattern Matching
– Supports ClamAV virus DB*
AIX is IPv6 Certified
AES support
IPSEC Suite

IP Filter is also known as IPF.
Open source internet protocol filtering tool
Acts as a firewall
Allows for consistent firewall rules tables in a heterogeneous
environment (AIX, HP, Solaris, Linux)
Provides NAT support
IP Filter

OpenSSH
– http://sourceforge.net/projects/openssh-aix
– Client and server connectivity encryption tool.
– Supports Triple DES & Blowfish encryption protocols.
– Eliminates clear text passwords and traffic over the
network.
– NLS Enablement
– Kerberos v5 as an optional authentication method.
– New version to ship in November, SSH 4.6
TCP Wrapper
– Open source tool that protects access to network
services such as telnet, ftp, r-commands, etc.
– It can be configured to explicitly deny or permit remote
hosts attempting to access these services.
– Monitors access to services and reports via a log file
and/or can be integrated into the AIX audit utility.
OpenSSH & TCP Wrapper

FIPS 140-2 Level 4 certified
Common Cryptographic Architecture (CCA) and PKCS11 APIs
PCI-X Cryptographic Coprocessor (4764)

On board API functionality:
– DES and 3DES encryption and message authentication
– RSA digital signatures (up to 2048 bits)
– DES, 3DES and RSA key management
Secure Electronic Transaction (electronic commerce functions)
ATM and POS PIN processing.
Key diversification for smart card applications
4764 CCA API Functionality

Banking and finance
Electronic commerce
Certificate Authorities
General purpose encryption services
Custom applications
– Limited basis under custom contracts.
CCA Applications

SED protects against the most common and exploited
vulnerability:
A stack buffer overflow, usually causes application and/or
operating system termination. More sophisticated attackers will
use it to escalate their privileges in order to gain control of the
system.
Stack Execution Disable (SED)

Stops buffer overflow based vulnerabilities
– Disables execution on the stack and heap
• Uses process page level protection
• Processor interrupts the OS on exceptions
Control granularity
– Off/On (all)
– Select
– setuid and setgid files
Two modes of operation
– Monitor & Operational
Logging
– Logged events are sent to the AIX error log
Stack Execution Disable: Administration

Offers system-wide protection of all files when ON
– Drawback is Java and GCC, which may legitimately
execute on the stack
Select file protections
– Network services
– Mission critical applications and services
setuid/getuid permission
– Protection against escalation of privileges
Stack Execution Disable: Administration cont.

Virtual IO Server v1.3 Security Enhanced
– Common Criteria certified EAL4+ under CAPP & LSPP
– Implements AIX Security Expert
– Fully customizable set of security policies
– Built in firewall
– 'viosecure' command enables and alters the state of the
firewall
• Default rule is, deny
• Limited set of network services permitted
Other System p AIX Offerings

Network and OS hardening tool
Result of hardening and security research
Brings 300+ security settings to a central point of control
Simplifies complex security configuration
Extensible to enterprise specific settings and software
Single system configuration applied to the whole enterprise
AIX Security Expert: Overview

Network and OS Security Hardening Tool
Knowledge of multitude of Unix hardening papers
Brings 300+ Security Settings to Central Control
Simplifies Complex Security configuration
Extensible to Enterprise specific settings and software
Configure one system, and apply template throughout the
enterprise.
AIX Security Expert: Bringing the Security Pieces Together

Security Expertise in the Tool
Simple Configuration Settings
– High, Medium, Low
Advanced settings
Each settings offers system admin selectable detail of settings.
Undo option
– Recursive undo of settings
Consistent Security Option for Enterprise
AIX Security Expert

AIX Security Hardening Groupings
– Password Administration
– Login Policy
– Audit
– /etc/inittab
– /etc/rc.tcpip
– /etc/inetd.conf
– remove SUID (remove bit from r-cmds)
– Network Tunning (‘no’ security options)
– IP Security (firewall) port scans
– Misc
AIX Security Expert

Simple Solid Design
Core engine never changes
Engine has no knowledge of High, Med, Low, Advanced, Undo
All security setting described in xml rules
Undo xml built dynamically
AIX Security Expert

Xml fomat /etc/security/aixpert/core/aixpertall.xml
<AIXPertEntry name="minagehls">
<AIXPertRuleType> 1 </AIXPertRuleType>
<AIXPertRuleState>Desired</AIXPertRuleState>
<AIXPertDescription> Specifies the minimum number of weeks to
1 week, before a password can be changed
</AIXPertDescription>
<AIXPertPrereqList> bos.rte.date, bos.rte.commands,
bos.rte.security, bos.rte.shell, bos.rte.ILS </AIXPertPrereqList>
<AIXPertCommand>/etc/security/aixpert/bin/chusrattr</AIXPertCo
mmand>
<AIXPertArgs>minage= 1 ALL minagehls</AIXPertArgs>
</AIXPertEntry>
AIX Security Expert

Security Configuration Saved in
– /etc/security/aixpert/core/appliedaixpert.xml
Configure one system, stamp appliedaixpert.xml on rest of
enterprise, for uniform security settings
– After configuring one system, the settingsimplemented on
that system are saved in appliedaixpert.xml file
– Via a secure out of band method, copy this file to other
systems
– Run a single command to implement these exact settings
on other systems
– /usr/sbin/aixpert –f appliedaixpert.xml
AIX Security Expert

Check Security compares current system configuration with
Check Security; has anything changed?
AIX Security Expert

Security Hardening at install time with Config Assist
AIX Security Expert can be accessed at install time via Config
Assist
AIX security settings unchanged unless user selects the
Configure Security from the Config Assist menu
– Default Config Assist Security Level is Low Level
Security
NIM Post Install script to automatically configure Security
AIX Security Expert

More on High, Medium, and Low Level Security
High
– Security is paramount
– On an unsafe network
Medium
– Safe network
– Clear text passwords over network is OK
Low
– Common non-disruptive security settings
Standard AIX
AIX Security Expert

Enhanced AIX Security Expert
Multilevel Security (MLS)
Role-based Access Control
Trusted Execution
AIX 5L 6.1 Security Features

appliedaixpert.xml distributed through LDAP
– No need for sneaker-net or secure copy
Performance boost
– XML parsing via C library routines
"Secure by Default"
– Initial installation is a minimal install
– High security level is applied during install
File Permission Manager
SOX/Cobit Compliance Assistant
– Wizard for setting up system to comply with SOX
requirements
Enhanced AIX Security Expert

#name program arguments
ftp /usr/sbin/ftpd ftpd
telnet /usr/sbin/telnetd telnetd -a
shell /usr/sbin/rshd rshd
login /usr/sbin/rlogind rlogind
exec /usr/sbin/rexecd rexecd
comsat /usr/sbin/comsat comsat
uucp /usr/sbin/uucpd uucpd
bootps /usr/sbin/bootpd bootpd /etc/bootp
finger /usr/sbin/fingerd fingerd
systat /usr/bin/ps ps -ef
netstat /usr/bin/netstat netsta -f inet
tftp /usr/sbin/tftpd tftpd -n
Secure by Default

#name program arguments
talk /usr/sbin/talkd talkd
ntalk /usr/sbin/talkd talkd
rquotad /usr/sbin/rpc.rquotad rquotad 100011 1
rexd /usr/sbin/rpc.rexd rexd 100017 1
rstatd /usr/sbin/rpc.rstatd rstatd 100001 1-3
rusersd /usr/lib/netsvc/rusers/rpc.rusersd rusersd 100002 1-2
rwalld /usr/lib/netsvc/rwall/rpc.rwalld rwalld 100008 1
sprayd /usr/lib/netsvc/spray/rpc.sprayd sprayd 100012 1
pcnfsd /usr/sbin/rpc.pcnfsd pcnfsd 150001 1-2
instsrv /u/netinst/bin/instsrv instsrv -r /tmp/netinstalllog /u/netinst/scripts
Secure by Default (Continued)

STOP giving out root users password
Distribute administration of the system to disparate and
unconnected users.
– i.e. Human resources creates the user, finance changes
the users salary, operations defines authorizations and
managements creates roles
The goal of RBAC is to reduce or eliminate the use of "root"
RBAC is installed and active by default
– Integrated into the kernel and installed commands
Role-Based Access Control

RBAC was previously provided by PitBull (AIX v5.3)
Limited set of roles
Authorizations are hard-coded into the command code
User “root” cannot be completely removed
Third party applications are required to code
authorizations into their commands
Role-Based Access Control: Background v5.3

Distribution of root roles to system users
– Gives user “cingram” the authority to create users, but
not give them access to set passwords
More levels of granularity than previously offered
– Users can assume a very specific role
– System-defined roles and user-defined roles
Integration into LDAP
– Authorization tables do not have to be stored locally
Option to eliminate the root user
– Removes the "golden egg" from the system
Reduces collaborative attacks from insiders
– Least privilege security model reduces exposure and
increases effort
Role-based Access Control

Suited to roles where there are many users managing a single
system
Government organizations
Datacenter operations
Database management
RBAC Environments

What is it?
– Security through classifications and labels (EAL4+
Labeled Security Protection Profile)
– Separate product and will NOT be included with the base
distribution
MLS via PitBull in AIX v5.3
MLS via AIX in v6.1
Expands on RBAC infrastructure
Multi-Level Security (MLS)

MLS details
– Add on security enhancement for AIX based on the
Trusted OS model
– Protects servers from internal and external attackers
– Compartmentalizes and secures applications
– Prevents malicious code from damaging systems
– Removes administrative (superuser/root) privileges
– Meets and exceeds government standards for maximum
security
Multilevel Security (MLS)

Federal government networks and databases (datacenters)
Banks and financial institutions
Healthcare (HIPAA requirements)
Public utilities
Service providers (application, eCommerce)
Large corporate datacenters
Any environment containing sensitive information
Value proposition:
– Provides maximum security for an organizations assets
– Provides lower overall costs for IT
– Permits for a simpler security architecture
– Maintains 100% compatibility with AIX applications
MLS Environments

Extension of current Trusted Computing Base
Provides both install time and run time integrity check
Loader verifies signature on files before they are executed
Trusted Execution

Scenario: Hacker replaces the existing /usr/bin/ls with his own:
– How do you scan the system to detect this change?
– How do you stop execution of the invalid executable?
– How do you prevent future modification of trusted
applications?
Scenario: Hacker places a trojan horse "ls" command on
system.
– How do you enforce where executables / libraries come
from?
The Need for Trusted Execution

Provides Signature Based System Verification
– Two modes of integrity checking:
• System: Comparison of current system with
stored database.
• Run-time: Validation of binary at execution time.
Cryptographic Hash Mechanism
– Supports SHA-1, SHA-256 and SHA-512
– Allows for signed hash signatures.
Configurable Policies
– Monitor all executions and loads of files in signature
database.
– Monitor only loads of kernel extensions.
– Monitor only loads of shared libraries.
– Lock the signature database. Even root cannot write to
database.
– Disable trusted file opens for write.
Trusted Execution

Integrity Checking
– TE - System and Run-time checking.
– TCB - System checking only.
System Enablement
– TE - Enabled at any time.
– TCB - Install time option.
Security Database
– TE - /etc/security/tsd/tsd.dat
– TCB - /etc/security/sysck.cfg
Management Commands
– TE – trustchk
– TCB - tcbck
Trusted Execution(TE) Comparison to TCB

Transparent to users and system administrators
File level encryption granularity
Centralization of key-store
– User key store allocated after successful login
Employs AES symmetric encryption algorithm
Integrated into the user administration
– Automatic generation of key-stores for every user
– Wraps users private key-store with the users password

AIX EFS offers file level encryption
– HP EVFS only offers logical volume level encryption
AIX EFS offers unique keying and crypto metadata per file
– HP EVFS only offers one key and crypto metadata per
logical volume
AIX EFS has the key-store connected to the users login
– HP EVFS requires a separate command
Competitive Analysis: AIX EFS vs. HP EVFS

AIX EFS is integrated into FS commands (i.e.: chmod)
– HP EVFS has a separate ‘evfs’ command and then it only
operates on the logical volume
AIX EFS backups are encrypted by default
– HP EVFS backups must be re-encrypted
AIX EFS volume groups can be resized as it is done today
– HP EVFS volume groups cannot be resized (-F (force)
option results in corrupted data
Competitive Analysis cont.

AIXpert - AIX Security expert

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