Computer Security and OpenSSL

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Questions and Answers

What is the primary goal of a denial-of-service attack?

To install malware on a system

To gain unauthorized access to a system

To make a network or server unavailable (correct)

To steal sensitive information

What is the purpose of the `getcifsacl` command?

To display the ACL of a file system (correct)

To set permissions on a file system

To unmount a file system

To mount a file system

What is the default timeout period for OpenVPN control packets?

10 seconds

2 seconds (correct)

1 second

5 seconds

What permission bit allows a user to modify a file?

Write Signup and view all the answers

What is the primary function of the `rkhunter` tool?

To detect rootkits and other security threats Signup and view all the answers

What is the purpose of a certificate chain?

To verify the authenticity of a digital certificate Signup and view all the answers

What iptables command changes the source IP address for all IPv4 packets going through the eth0 interface?

iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source 192.0.2.11 Signup and view all the answers

What is the purpose of the ACL prefix 'OWNER' in the output of `getcifsacl`?

To specify the owner of a file system Signup and view all the answers

What is the primary function of the NSEC or NSEC3 records in a DNS zone?

To prevent zone enumeration Signup and view all the answers

What is the main purpose of a PTR record in a DNS zone?

To map an IP address to a hostname Signup and view all the answers

What is the primary function of a Certificate Revocation List (CRL)?

To list X.509 certificates that have been revoked Signup and view all the answers

What is the main purpose of a DNSKEY record in DNSSEC?

To sign a DNS zone Signup and view all the answers

What is the primary goal of phishing attacks?

To steal sensitive information from a victim Signup and view all the answers

What is the main purpose of AIDE?

To detect intrusions and system changes Signup and view all the answers

What is the primary goal of social engineering attacks?

To trick victims into divulging sensitive information Signup and view all the answers

What is the primary function of host intrusion detection (HID) systems?

To monitor and detect potential security threats on a single computer or server Signup and view all the answers

What is the primary function of the chkrootkit tool?

To scan a Linux system for rootkits Signup and view all the answers

What happens when the getfattr command is run on a file with no extended attributes set?

No output is produced and it exits with a value of 0 Signup and view all the answers

What is the correct command to delete the second key of a LUKS device?

cryptsetup luksDelKey /dev/sda1 2 Signup and view all the answers

What is a characteristic of eCryptfs?

It does not support encryption of home directories for regular Linux users Signup and view all the answers

What command is used to disable automatic password expiry for a user?

chage --maxdays -1 username Signup and view all the answers

What is the purpose of OpenSCAP?

To monitor system processes for security compliance Signup and view all the answers

What is the function of the rpm command?

To verify the integrity of RPM packages Signup and view all the answers

What is a characteristic of a LUKS device?

It can have multiple keys Signup and view all the answers

What parameter in OpenSSL specifies the host name for TLS Server Name Indication?

-servername Signup and view all the answers

What type of extension is added to a certificate for the host names example.org and www.example.org?

X 509v3 Subject Alternative Name Signup and view all the answers

What is a buffer overflow?

A software vulnerability Signup and view all the answers

Which tool is used to manage the Linux Audit system?

auditd Signup and view all the answers

What is the difference between a SetUID and SetGID bit?

SetUID allows a file to be executed with the permissions of the file owner, while SetGID allows a file to be executed with the permissions of the group owner Signup and view all the answers

What is a valid AIDE rule?

!/var/run/.* Signup and view all the answers

What command in the Linux Audit system provides searching and filtering of the audit log?

ausearch Signup and view all the answers

What is the purpose of the TLS Server Name Indication extension?

To specify a host name for a TLS connection Signup and view all the answers

What is the primary purpose of a Certificate Revocation List?

To allow a server to provide proof of the revocation status of certificates Signup and view all the answers

What is the command to install and configure a new FreeIPA server?

ipa-server-install Signup and view all the answers

What is the OpenSSL command to generate a certificate signing request (CSR) using an existing private key?

openssl req –new –key private/keypair.pem –out req/csr.pem Signup and view all the answers

What is Cryptography?

The art of sending secret messages Signup and view all the answers

What type of activity does HID monitor for?

Unauthorized access attempts Signup and view all the answers

What is NOT a benefit of using HID?

Provides automatic removal of detected threats Signup and view all the answers

What is the term for the encrypted message?

Ciphertext Signup and view all the answers

What is the purpose of a Certificate Authority?

To issue certificates to servers Signup and view all the answers

Study Notes

OpenSSL Parameters

-servername specifies the host name to use for TLS Server Name Indication.

OpenSSL Configuration

The line subjectAltName = DNS: www.example.org, DNS:example.org adds an X.509v3 Subject Alternative Name extension for the host names example.org and www.example.org to a certificate.

Security Threats

A buffer overflow is a type of software vulnerability.
Phishing is a type of social engineering attack.

Linux File Permissions

SetUID allows a file to be executed with the permissions of the file owner.
SetGID allows a file to be executed with the permissions of the group owner.
The permission bit Write allows a user to delete a file.

Linux Audit System

The command auditd is used to manage the Linux Audit system.
The command aureport provides searching and filtering of the audit log.

AIDE

AIDE is used to detect intrusions and system changes.
The command aide is used to manage system audits.

OpenVPN

OpenVPN sends a control packet to its peer and expects an acknowledgement in 2 seconds by default.
The option --tls-timeout 5 changes the timeout period to 5 seconds.

Certificate Management

A certificate chain is a sequence of certificates used to verify the authenticity of a digital certificate.
A Certificate Revocation List (CRL) is a list of X.509 certificates that have been revoked by a particular CA.

DNS and DNSSEC

The DNS record PTR is used to map an IP address to a hostname.
The DNS record DNSKEY is used to sign a DNS zone.

Host Intrusion Detection

HID monitors for unauthorized access attempts.
HID does not provide automatic removal of detected threats.

Cryptography

Cryptography is the art of sending secret messages.
A ciphertext is the encrypted message.

Disk Encryption

The command cryptsetup is used to manage disk encryption.
The command getfattr is used to check for extended attributes on a file.

eCryptfs

eCryptfs is a system that encrypts files and directories.
eCryptfs does not store the contents of all files in an archive file.
eCryptfs can be used to encrypt only directories that are the home directory of a regular Linux user.

FreeIPA

The command ipa-server-install installs and configures a new FreeIPA server, including all sub-components, and creates a new FreeIPA domain.

Rootkit Detection

The command chkrootkit is used to detect rootkits on a Linux system.
The command rkhunter is used to detect rootkits and other security threats.

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Description

This quiz covers various aspects of computer security, including OpenSSL parameters, configuration, and common security threats. It also touches on Linux file permissions.