Wi-Fi Security Protocols: WEP, WPA2, WPA3

Wireless networks broadcast signals through the air, crossing physical boundaries that wired networks respect. Anyone within range of a Wi-Fi signal can attempt to connect or capture traffic without physically accessing a building. This makes wireless inherently more exposed than wired networks. Security protocols — WEP, WPA, WPA2, and WPA3 — were developed progressively to address weaknesses found in their predecessors. Understanding this evolution is critical for the Security+ exam and for auditing real-world wireless environments.

WEP (Wired Equivalent Privacy) was the original 802.11 security standard introduced in 1997. It used a 40-bit (later 104-bit) key with the RC4 stream cipher and a 24-bit Initialization Vector (IV). The IV was far too small — with only 16 million possible values, IVs repeat rapidly on busy networks. Attackers could collect enough frames with repeated IVs to recover the secret key using statistical analysis. Tools like Aircrack-ng can crack WEP in minutes by capturing as few as 50,000 packets. WEP is completely broken and must never be used.

WPA (Wi-Fi Protected Access) was released in 2003 as an emergency fix while the 802.11i standard was being finalized. WPA introduced TKIP (Temporal Key Integrity Protocol), which added a per-packet key mixing function and a sequence counter to address WEP's IV reuse problem. It also added a Message Integrity Check (MIC) called Michael to detect packet tampering. However, TKIP still uses RC4 and inherits some weaknesses. WPA was designed to run on existing WEP hardware via firmware update and is now considered deprecated.

WPA2 implements the full IEEE 802.11i standard and replaced WPA as the mainstream Wi-Fi security protocol in 2004. The critical improvement is CCMP (Counter Mode with CBC-MAC Protocol), which uses AES instead of RC4. AES-CCMP provides both encryption and integrity protection using a 128-bit key. WPA2 has two modes: Personal (PSK) uses a shared passphrase and is suitable for homes and small offices, while Enterprise (802.1X/RADIUS) uses individual certificates or credentials per user for corporate environments.

WPA2-PSK security depends on the 4-way handshake that occurs when a client connects. Both the AP and client prove they know the Pre-Shared Key by exchanging nonces and computing a Pairwise Transient Key (PTK). An attacker who captures this handshake can attempt an offline dictionary attack — testing millions of passwords — without interacting with the AP. The newer PMKID attack (2018) extracts a single PMKID frame from the first EAPOL message, removing the need to capture a full client authentication, making passive capture unnecessary for cracking WPA2-PSK.

WPA3 was introduced in 2018 to address WPA2's weaknesses. Its most important improvement is replacing the PSK 4-way handshake with SAE (Simultaneous Authentication of Equals), also called Dragonfly. SAE provides forward secrecy — captured traffic cannot be decrypted retroactively even if the password is later compromised — and prevents offline dictionary attacks because each login attempt requires interacting with the AP. WPA3-Enterprise mandates 192-bit security suite for sensitive environments. WPA3 also introduces Enhanced Open (OWE) that encrypts open networks without requiring a password.

PMF (Protected Management Frames), defined in 802.11w, provides integrity protection for management frames like deauthentication and disassociation. Without PMF, these frames are unauthenticated and can be forged by anyone within radio range, enabling deauthentication attacks that kick clients off a network. PMF is optional in WPA2 but mandatory in WPA3. Enabling PMF in WPA2 networks blocks most deauth-based attacks, including the prerequisite step for many evil-twin and handshake capture attacks.

WPS (Wi-Fi Protected Setup) was designed to simplify connecting devices to WPA2 networks using an 8-digit PIN or push-button. The PIN method is critically flawed: the 8-digit PIN is actually two independent 4-digit PINs validated separately, reducing the keyspace from 100 million to 11,000 combinations. The Reaver and Bully tools can brute-force a WPS PIN in hours. Even after locking out, some APs reset the lockout timer. The PIN-based WPS should be disabled entirely; push-button WPS has a narrower attack window but still poses risk.

Choosing strong encryption for your wireless network involves selecting the right protocol and configuration. The recommended hierarchy from strongest to weakest is: WPA3-Enterprise > WPA3-Personal > WPA2-Enterprise > WPA2-Personal. For WPA2/3-Personal, use a passphrase of at least 20 random characters to resist offline dictionary attacks. Avoid TKIP entirely — use CCMP/AES only. Configure cipher suites explicitly rather than allowing mixed mode, which may negotiate down to weaker ciphers for backwards compatibility with older devices.

The Security+ exam frequently tests your ability to compare wireless protocols. Key differentiators: WEP uses RC4 with a broken short IV — always the wrong choice. WPA/TKIP is deprecated and also uses RC4. WPA2/CCMP uses AES and is the current minimum acceptable standard. WPA3/SAE adds forward secrecy and eliminates offline dictionary attacks. Enterprise mode (802.1X/RADIUS) is always more secure than Personal/PSK mode for organizations. Memorize these distinctions and why each was introduced.

Many compliance frameworks mandate specific wireless security controls. PCI-DSS requires WPA2 or higher with AES encryption for any wireless network in scope for cardholder data. Organizations must also inventory all wireless access points quarterly and test for rogue APs. HIPAA requires encryption of wireless data containing PHI. Auditors look for network documentation, encryption standards, rogue AP detection programs, and periodic wireless vulnerability assessments. Failing to upgrade from WEP or WPA/TKIP in a PCI environment can result in significant penalties.

Test your understanding of CompTIA Security+ (SY0-701) concepts from this lesson.

In this lesson you learned: WEP is completely broken due to its short IV and RC4 weaknesses and must never be used, WPA2/CCMP uses AES but WPA2-Personal is vulnerable to offline dictionary attacks against captured 4-way handshakes, and WPA3/SAE provides forward secrecy and prevents offline cracking by requiring active AP interaction. Next up we explore specific wireless attacks including evil twin and deauthentication techniques.