From: 2weiEmu Date: Wed, 16 Apr 2025 20:17:45 +0000 (+0200) Subject: addition to CS cheatsheet X-Git-Url: https://git.saalbach.dev/?a=commitdiff_plain;h=207b35bee54f5da22349faa5156c5ef5ff7ce200;p=research-obsidian.git addition to CS cheatsheet --- diff --git a/.obsidian/app.json b/.obsidian/app.json index dd6a8ed..1735354 100644 --- a/.obsidian/app.json +++ b/.obsidian/app.json @@ -6,7 +6,7 @@ "includeName": true, "pageSize": "A4", "landscape": false, - "margin": "0", + "margin": "2", "downscalePercent": 100 }, "promptDelete": false diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json index d37f7ae..a23dd30 100644 --- a/.obsidian/workspace.json +++ b/.obsidian/workspace.json @@ -13,7 +13,7 @@ "state": { "type": "markdown", "state": { - "file": "People/Ruxi.md", + "file": "University/Computer Security/Cheatsheet (extensive, draft).md", "mode": "source", "source": false, "backlinks": true, @@ -28,7 +28,7 @@ } }, "icon": "lucide-file", - "title": "Ruxi" + "title": "Cheatsheet (extensive, draft)" } } ] @@ -54,7 +54,7 @@ "autoReveal": true }, "icon": "lucide-folder-closed", - "title": "Files" + "title": "File explorer" } }, { @@ -161,10 +161,10 @@ }, "left-ribbon": { "hiddenItems": { + "daily-notes:Open today's note": false, "switcher:Open quick switcher": false, "graph:Open graph view": false, "canvas:Create new canvas": false, - "daily-notes:Open today's daily note": false, "templates:Insert template": false, "command-palette:Open command palette": false, "excel:Create Excel File": false, @@ -175,8 +175,10 @@ }, "active": "b32655feb9b7d9db", "lastOpenFiles": [ + "Pasted image 20250416221211.png", + "Pasted image 20250416221155.png", "People/Ruxi.md", - "University/Computer Security/Cheatsheet (mmm for exam).md", + "University/Computer Security/Cheatsheet (extensive, draft).md", "University/Human Computer Interaction/Untitled.md", "University/Computer Security", "University/Human Computer Interaction", @@ -211,7 +213,6 @@ "Bundesverfassungsgericht/References on Bundesverfassungsgericht.md", "University/Algorithm Design/Resources.md", "University/Algorithm Design/Greedy.md", - "AI/Thoughts on the Ethics of AI.md", "People", "University/HCI", "University/Algorithm Design", diff --git a/Pasted image 20250416221155.png b/Pasted image 20250416221155.png new file mode 100644 index 0000000..b6a478a Binary files /dev/null and b/Pasted image 20250416221155.png differ diff --git a/Pasted image 20250416221211.png b/Pasted image 20250416221211.png new file mode 100644 index 0000000..f5f8cc9 Binary files /dev/null and b/Pasted image 20250416221211.png differ diff --git a/University/Computer Security/Cheatsheet (extensive, draft).md b/University/Computer Security/Cheatsheet (extensive, draft).md new file mode 100644 index 0000000..fe30654 --- /dev/null +++ b/University/Computer Security/Cheatsheet (extensive, draft).md @@ -0,0 +1,159 @@ +# Network Sec. +## Firewalls +1. **Packet Filtering Firewall**: Simple firewall that checks packet (semi-) independently. +2. **Application-Level Firewall**: More complex traffic patterns, allowing finer control (but requires more resources) + +Layered Defence: + Implement a multi-layered security approach to address different levels of threats. + +### Threat vs. Harm +> Threat = A potential danger that could cause harm +> Risk = The likelihood that the threat will actually exploit a vulnerability and cause damage +Risk = Likelihood * Impact + +Threat Model: + A strategic framework that identifier potential attacks and adversaries + +## Types of Threat Actors +| Threat Actor | Motivation | +| ---------------- | -------------------- | +| Cybercriminal | Profit | +| Nation State | Geopolitical | +| Terrorist Groups | Ideological Violence | +| Thrill-Seeker | Satisfaction | +| Insider Threats | Discontent | +| Hackers | Variable | + +Coordinated Vulnerability Disclosure (CVD): + CVD is an ethical practice where security researchers or individuals who discover a vulnerability responsibly report it + +Bug Bounties: + Ethical hackers hunt for rewards in discovering and report vulnerabilities. + + +### Cyber Kill Chain: +1. Recon +2. Weaponisation +3. Delivery +4. Exploitation +5. Installation +6. Command and Control (C2) +7. Actions on Objectives + +Detecting Criminals can be based on multiple things: +1. Hash Values +2. IP Addresses +3. Domain Names +4. Network / Host Artifacts +5. Tools +6. Tactics, Techniques and Procedures + +Defense in Depth: cybersec. strategy that involves deploying multiple layers of security (layered security) + +Usable Security: If your security is not very usable this can pose its own security risks. + +CIA Triad: + The CIA Triad contains the three security essential goals in Cyber Security + 1. Confidentiality + 2. Integrity + 3. Availability + +Confidentiality can be achieved with: +- Encryption +- Access Control Systems +- Policies an Governance + +Integrity with: +- Data validation +- Change Management and Version Control + +Availability: +- Redundancy and failover +- Load balancing +- Monitoring and alerting + +# Physical Layer +This includes: Servers, Cabling, Storage Devices, Network Equipment, Acess Points and Entry doors. You need to limit this kind of access, otherwise even the most secure system is vulnerable. + +Access control: + Only the people that should have authorised access, should be able to go there. + +Types of Access Control: +- Physical Barriers +- Authentication Systems +- Surveillance & Monitoring +- Visitor Management + +Cables can be tapped. +This can be detected, either with phyiscal inspection, signal strength analysis and cable testing. You can both tap glass-fibre and copper. + +Cables can generate Electro-magnetic interference. +Rodent and Pest Damage. + +Typically critical systems are air-gapped, can only be acccessed from specific places, that are physically protected. +Sometimes even with data diodes. + +**Guided Medium**: + A communication channel where the signals are guided along a physical path. + e.g. Copper Cables, Fibre Cables etc. etc. + Physical access is needed + +**Unguided Medium**: + Refers to a communication channels where the signals propagate freely through the air or space + e.g. Radio or Infrared + +Unguided can be controlled through range, directional attenas etc. + +Signal security: +- Spread signals to prevent jamming +- Frequency hopping aims to change freqs. very fast in a pattern that is unknown to an attacker +- Authenticating and encrypting data sent over wireless can ensure integrity and confidentiality + +Spoofing: In the case of IP Spoofing, making a server's response to go someone else, not you. +Denial of Service: An Attack that floods a victim's network with traffic, making it unavailable + +Types of DDoS: +- Volumetric Attack (loads of stuff) +- Protocol Attacks (break the protocol in some way) +- Application Layer Attacks (target specific apps) + +Volumetric: +Amplification Attack: Use an intermediary that returns a large response, in order to overwhelm stuff. + +Can be done with a lot of protocols: commonly UDP. +People love DNS to do DoS + +Protocol: +TCP SYN Flood is a common protocol attack +You Spoof a SYN packet, and make it send SYN ACKS to people, and because the bot doesn't ever send an 'ACK' it leaves the server waiting, and sometimes wasting memory space. + +This can be mitigated by, e.g. not using memory to keep this state but using a crypto validation instead on the number. + +The SYN-ACKS that go nowhere are 'backscatter' + +Application lyer attack: HTTP Flood +Cannot be spoofed. Requests a lot of large files. +Cannot be spoofed because HTTP requires TCP. + +HTTP/2 RAPID RESET ATTACK +Request, and Reset, all the time + +![[Pasted image 20250416221155.png]] + + +![[Pasted image 20250416221211.png]] +HTTP 2 attack + +How to mitigate DDoS attacks: +- Redundant network infrastructure (no single point of failure) +- Traffic filtering +- Content Delivery Networks (distribute and cache content) +- Web Application Firewalls (try to identify malicious traffics) + +Botnets: +A botnet is a network of compromised computers that are under the control of a single entity, usually a malicious actor. +Spreading malware, stealing sensitive info, DDoS + +Architecture: +Infected Devices, Command and Control (C2), Communications Channels (basically everything is used here) + diff --git a/University/Computer Security/Cheatsheet (mmm for exam).md b/University/Computer Security/Cheatsheet (mmm for exam).md deleted file mode 100644 index e69de29..0000000