OasisInterview Flashcards
What is CSRF?
Cross site request forgery is a web application vulnerability where the server does not check whether the request comes from a trusted client or not. The request is processed directly.
What is security misconfiguration?
Security misconfiguration is a vulnerability when a device/application/network is configured in a way which can be exploited by an attacker to take advantage of it. This can be leaving the default username/password unchanged or too simple for device accounts etc.
Definitions of black hat, white hat and grey hat hacker
Black hat: hack without authority.
White hat: authorized to perform hacking
Grey hats: white hat who sometimes perform unauthorized activities
What is a firewall?
Device that blocks/allows traffic as per defined by a set of rules. Placed as boundaries of trusted and untrusted networks
How do you keep yourself updated with information security news?
I follow threatpost and occasionally listen to podcasts like Cybersecurity weekly.
CIA triangle
Confidentiality
Integrity and availability
Explain risk, vulnerability and threat
Risk: measure of potential loss when the vulnerability is exploited by threat
Vulnerability: weakness in a system
Threat: when an attacker exploits a vulnerability
Difference between asymmetric and symmetric encryption and which is better
Symmetric encryption: is the same key for both encryption and decryption. Faster but is transferred over an unencrypted channel
Asymmetric: uses different keys. More secure but slow
Hybrid approach is best. Setting up a channel using asymmetric encryption and sending data over symmetric process
What is an IPS and how does it differ from IDS
IPS (intrusion prevention system): will detect and also take action to prevent intrusion (more noisy)
IDS (intrusion detection system): detect the intrusion and administrator decides what to do next
What is XSS and how will you mitigate it?
Cross site scripting is JavaScript vulnerability in the web applications. User enters script in client side input fields and that input gets processed without validation. Leading to untrusted data getting saved and executed on client side
Example: hacking of MySpace
Countermeasure: input validation, implementing CSP (content security policy)
What is difference between encryption and hashing?
Encryption: reversible. Ensures confidentiality
Hashing: can be cracked but is not reversible. Ensures integrity
HIDS vs NIDS and which one is better and why?
HIDS (host intrusion detection system):
Placed on the host
NIDS (network intrusion detection system): placed on the network
Placement is different
What is port scanning?
Process of sending messages to gather information about network, system, etc. analyzing responses received
Nmap command
Also netstat
Difference between VA and PT
VA: vulnerability assessment: finds flaws in application/network
PT (penetration testing): of finding exploitable vulnerabilities
VA is on the surface and PT is more in depth
What is WAF and it’s types?
WAF: web application firewall. Used to protect the application by filtering legitimate traffic from malicious traffic. Can be box or cloud based
Explain objects of basic web architecture
Front ending server (provides scalability), web application server (hosts applications) and database server
Difference between policies, processes and guidelines
Policies: defines security objectives and security framework of an organization
Process: detailed step by step how to document that specifies the exact action to necessary to implement important security mechanism
Guidelines: recommendations
What is false positive and false negative?
False positive: false alarm. No threat
False negative: intrusion has taken place and there is no alarm
How to harden a server?
Close unused ports, create accounts with least privilege permissions, disable remote access for admin and root accounts
What is the difference between UDP and TCP?
UDP: kind of a shot in the dark. Could miss some packets. An example is live-streaming
TCP: when each packet is accounted for. For example Netflix
OSI model
Physical Data link Network Transport Session Presentation Application
Port of file transfer protocol (FTP)
Transport protocol: TCP
20, 21
20: data transfer
21: control
Used for transferring files on internet or private network
Secure shell (SSH)
Uses TCP and UDP
Primary method used to manage network devices on the command level. Secure Alternative to Telnet
22
Telnet port
Uses TCP
23
Primary method used to manage network devices at the command level. Insecure connection
Simple mail transfer protocol (SMTP)
Uses TCP
25
Used for transferring mail (email) from source to destination and mail servers and used for end users to send emails
IPSec
50, 51
Dynamic host configuration protocol (DHCP)
UDP
69
Used on networks that do not use static IP address assignment. Set up by admin with a poll of addresses that are available for assignment
Trivial file transfer protocol (TFTP)
Uses UDP
69
Method of file transfer (like FTP but without session establishment—uses UDP instead of TCP).
Hyper text transfer protocol (HTTP)
Uses TCP
80
Main protocol used by web browsers
Post office protocol (POP3)
Uses TCP
110
Retrieve mail from server.
HTTP with secure sockets layer (SSL)
TCP and UDP
443
FTP over SSL/TLS
Uses TCP
989,990
Remote Desktop protocol
TCP and UDP
3389
Domain name system (DNS)
TCP/UDP
53
Used on public internet and on private networks to translate domain names into IP addresses.
Network time protocol (NTP)
UDP
123
Synchronized devices on the Internet
NetBios
TCP/UDP
137/138/139
Not a protocol but is used with IP with the NetBios over TCP/IP (NBT) protocol.
Internet message access protocol (IMAP)
TCP
143
Like POP (receivers mail), but supports wider array of remote mailbox operations
Simple network management protocol (SNMP)
TCP/UDP
161/162
For network management. Monitor, configure and control
