Bridging Code and Security: SQL Injection, Hardening and Network Basics | GCF Parul University (Part 1)

Last week I did a one-week cybersecurity training at Parul University, through the Global Certification Forum (GCF). Certificate at the end. The syllabus was Pearson’s IT Specialist Cybersecurity objectives, so it’s pitched at entry-level technicians and junior analysts.

A lot of it, I’d already seen in my CSE classes. A couple of topics were new. What I didn’t expect was how many gaps showed up once I had to cover everything in five days instead of a semester.

This is Part 1, the first three of five domains. If you write code and security has only ever shown up in code reviews, this is a rough map.

The five domains:

1. Security Principles
2. Securing the Network
3. Securing Endpoint Devices
4. Vulnerability Assessment and Risk Management
5. Incident Handling

1. Security principles
This domain is the vocabulary. CIA triad, defense-in-depth, Zero Trust, hardening, data classification, governance. Then the frameworks: NIST CSF, ISO/IEC 27000 and the CIS Controls. They sound dry, but you’ll hear them in every real security conversation.

The attack list is long. If you write code, the ones to care about are SQL injection, input manipulation and buffer overflow. Privilege escalation and brute force aren’t far behind. Social engineering gets its own section: spear phishing, vishing, smishing, whaling, watering holes, tailgating, malicious QR codes. The syllabus also says AI and bots are making these attacks more convincing. That’s the one line I keep thinking about.

Access management (AAA, RADIUS, MFA) and encryption (symmetric vs. asymmetric, hashing, PKI, data in transit, at rest and in use) round it out.

SQL injection, from the PortSwigger labs
We did a few SQL injection labs on PortSwigger’s Web Security Academy. I knew the theory already. It didn’t really stick until I got past a login page myself.

The bug is simple. This code glues the user’s input straight into the query:

python

Vulnerable: user input is concatenated into the query

def login(conn, username, password):

    query = (

        "SELECT * FROM users WHERE username = '" + username +

        "' AND password = '" + password + "'"

    )

    return conn.execute(query).fetchone()

So the input stops being data and becomes part of the SQL. The fix is a parameterized query:

python

Safer: parameterized query

def login(conn, username, password_hash):

    query = 'SELECT * FROM users WHERE username = ? AND password_hash = ?'

    return conn.execute(query, (username, password_hash)).fetchone()

That’s what “input validation and sanitization” means in the syllabus. (It also assumes hashed passwords, which is the other half of doing this properly.) The labs are free, so just go do them.

2. Securing the network
This domain is about why common protocols are risky and what to put around them. The easy part is the pairs:

You’re also expected to know the weak spots of TCP, ARP, ICMP, DHCP, DNS, SMTP, SNMP, CDP/LLDP and syslog. The defenses are segmentation (DMZs, VLANs), NAT, firewalls, ACLs, IDS/IPS, proxies, honeypots, VPNs, NAC and cloud security groups. Wireless gets a short section too: MAC filtering, encryption standards, SSID.

The part I liked most was reading firewall and IDS logs. You’re not just collecting data. You’re asking whether it looks normal.

3. Securing endpoint devices
The most hands-on domain. It covers hardening Windows, macOS and Linux (permissions, disk encryption, CIS benchmarks), patching, compliance (PCI DSS, HIPAA, GDPR), system logs and malware removal.

The tools it names: netstat and ss for connections, nslookup for DNS, nmap and zenmap for scanning, Wireshark and tcpdump for packet capture. A few to try on a Linux machine you own:

bash

What is listening on this machine?

ss -tulpn

Which services and versions are exposed on your own host?

nmap -sV 127.0.0.1

Watch DNS traffic (needs root)

sudo tcpdump -i any port 53

One thing I didn’t know: malware can infect restore points and backups. So removal isn’t just running a scan. It’s containment, quarantine, treatment and inoculation.

What’s next
Part 2 covers vulnerability assessment, risk management, penetration testing, incident handling, and Stapler, a VulnHub machine I found properly challenging.

If a lab or resource made security click for you, drop it in the comments. I’m always looking for new ones.