Linux Security in Operating System

Linux Security in Operating System

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  BIRLA INSTITUTE OF TECHNOLOGY,MESRA JAIPUR Presented By Anushka Pareek MCA/25024/18 TOPIC : LINUX SECURITY
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  INTRODUCTION  Being amulti-user system - Linux have a tremendous amount of security to offer; many being open source, which can be validated and modified to meet anyone’s needs.  Security mechanisms allow users to service their legitimate needs without compromising the server system security.  Resource and file management maintain integrity  User privileges are granted.  Overall system stability and correctness do not suffer.
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  AUTHENTICATION  User entersusername and password via login  Passwords are hashed .  Encryption cannot be reversed  Stored in /etc/passwd or /etc/shadow  Pluggable authentication modules (PAMs) Can reconfigure the system at run time to include enhanced authentication techniques  Supports smart cards, Kerberos and voice authentication
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  Understanding the /etc/passwd
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  CRYPTOGRAPHY  Enables usersto access several forms of encryption to protect their data  Uses powerful algorithms such as DES, AES and MD5  Kernel uses Cryptographic API to implement IPSec  Enables users to create secure (encrypted) file systems  Loopback device: Layer between the virtual file system and the existing file system Can be used to encrypt and decrypt data transferred between processes and the underlying file system
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  Loopback device providingan encrypted file system using the Cryptographic API.
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  ADMINISTERING TRUSTED USERSAND HOSTS  The .rhosts file exists in a user's home directory  Specifies trusted hosts based on the users choice  More headaches for administrator - loss of control  Solution - disable or monitor contents.
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   In /etc/pam.d/limits.conf Limit processes per user.  Limit memory usage. LIMITING USER ACCESS TO SYSTEM RESOURCES
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  SYSTEM SECURITY VIEW Rootof Trust (e.g., TCG/TPM) Virtualization Layer Linux Kernel Other System Trusted Application Application User authentication Access control (transitions) Firewall Port scan IDS Crypto, Protocol, Access control Administration Set Access Policy Audit IDS Patch Harden
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  ACL/MAC PERMISSIONS Access ControlList  Almost modern files systems, include ACLs to give unprivileged access to only certain users.  Permissions are separated by owner , group , and others . Permissions are displayed as rwx rwx rwx Mandatory Access Control  More sophisticated form of permissions handling. This is more like application patching, it limits what permission each program is given.  MAC programs include: AppArmor, SELinux, SEBSD, GrSecurity, Trusted Solaris and Trusted BSD.
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  MEMORY ACCESS  Eachprocess has its own page table.  All memory access via page table.  Easy for OS to terminate process which references an invalid memory address.  Access control information for page held in the page table entry (PTE).  Prevents executable code from being overwritten  Separates kernel code and user code.
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  FIREWALLS  Firewalls aremeans of controlling what information is allowed into and out of your local network.  Linux Firewalls are ;- IPTables SELinux Scalable Robus
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  GRAPHICAL FIREWALL CONFIGURATION UTILITIES Linux supports several graphical tools that can be used to set up a firewall  Red Hat Linux includes the lokkit program that walks you through questions and establishes rules based on your security choices  Red Hat Linux also includes the firewall-config program, which allows the set up of complex firewall rules
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  CONCLUSION  Linux isa versatile OS.  Security implementation in the OS is spread throughout the system - memory management, file management, process management, etc.  Therefore every aspect of security needs to be configured from scratch since default is not maximum security.
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  THANK YOU