Question 335 of 1,013
SY0-701 Threats, Vulnerabilities, and Mitigations Practice Question
A security analyst is reviewing the session management implementation of a web application. The application generates session tokens by computing the MD5 hash of the concatenation of the username and the current server timestamp rounded to the nearest hour. An attacker has obtained a valid session token for her own account and discovers that she can forge tokens for other users by simply substituting the username in the hash calculation with a known target username. Which type of attack is the web application most vulnerable to?
⚠ Common exam trap
Candidates often confuse session prediction with session hijacking via XSS or session replay, but the key clue is that the attacker can compute the token herself by substituting the username, which directly indicates a predictable token generation scheme.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Session prediction
The session token is generated using MD5(username + timestamp rounded to the nearest hour). Since the attacker knows her own token and can compute the hash for any username with the same timestamp, she can predict tokens for other users. This is a classic session prediction vulnerability, as the token generation lacks sufficient entropy and relies on predictable inputs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Session hijacking via cross-site scripting (XSS)
Why it's wrong here
Session hijacking via XSS would require the attacker to successfully inject and execute malicious JavaScript in the victim's browser, typically using document.cookie to exfiltrate the session token. This scenario describes no injection vector or client-side script execution; instead, the weakness lies entirely in the server-side token generation algorithm (username plus low-granularity timestamp). Because the attacker can compute valid tokens offline without any interaction with the victim, the flaw is predictable token generation, not script-based theft.
When this WOULD be correct
A web application stores session tokens in cookies without HttpOnly or Secure flags, and an attacker exploits an XSS vulnerability to steal a victim's cookie and impersonate them. The question would describe a stored/reflected XSS that allows cookie theft.
- ✗
Session replay attack
Why it's wrong here
A session replay attack involves capturing a valid token and reusing it later to impersonate the same user. The vulnerability described allows the attacker to create a token for a different user, not replay a captured one.
When this WOULD be correct
A session replay attack would be correct if the question described an attacker intercepting a valid session token (e.g., via network sniffing) and reusing it to gain unauthorized access, without needing to modify the token or understand its generation method.
- ✓
Session prediction
Why this is correct
The session token is generated using the username and a timestamp with low granularity, making it possible for an attacker who knows the algorithm to calculate valid tokens for any user. This is a classic session prediction vulnerability.
- ✗
Session fixation
Why it's wrong here
Session fixation occurs when an attacker forces a victim to use a session token that the attacker knows. Here, the attacker is able to compute a token for the victim without any interaction, so it is prediction, not fixation.
When this WOULD be correct
A web application accepts session tokens from URL parameters and does not regenerate the token after login. An attacker sends a victim a link with a predefined session ID, and after the victim logs in, the attacker uses that same session ID to hijack the session.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SY0-701 exam frequently reuses these exact scenarios with slightly different constraints.
✓Session predictionCorrect answer▾
Why this is correct
The session token is generated using the username and a timestamp with low granularity, making it possible for an attacker who knows the algorithm to calculate valid tokens for any user. This is a classic session prediction vulnerability.
✗Session hijacking via cross-site scripting (XSS)Wrong answer — click to see why▾
Why this is wrong here
The vulnerability is in the predictable token generation (MD5 of username + timestamp), not in stealing tokens via XSS. The attacker forges tokens without needing to inject scripts or steal cookies.
★ When this WOULD be the correct answer
A web application stores session tokens in cookies without HttpOnly or Secure flags, and an attacker exploits an XSS vulnerability to steal a victim's cookie and impersonate them. The question would describe a stored/reflected XSS that allows cookie theft.
Why candidates choose this
Candidates may confuse any session-related attack with session hijacking, and XSS is a common vector for stealing tokens, but here the token is forged, not stolen.
✗Session replay attackWrong answer — click to see why▾
Why this is wrong here
A session replay attack involves capturing a valid session token and reusing it later to impersonate a user. In this scenario, the attacker is forging tokens for other users by manipulating the token generation algorithm, not replaying a captured token.
★ When this WOULD be the correct answer
A session replay attack would be correct if the question described an attacker intercepting a valid session token (e.g., via network sniffing) and reusing it to gain unauthorized access, without needing to modify the token or understand its generation method.
Why candidates choose this
Candidates may confuse 'replay' with any attack that involves using a token obtained from one session in another, overlooking that replay specifically requires capturing and reusing an existing token without alteration.
✗Session fixationWrong answer — click to see why▾
Why this is wrong here
Session fixation requires an attacker to force a victim to use a known session ID, but here the attacker can compute valid tokens for any user without needing to fixate a session ID.
★ When this WOULD be the correct answer
A web application accepts session tokens from URL parameters and does not regenerate the token after login. An attacker sends a victim a link with a predefined session ID, and after the victim logs in, the attacker uses that same session ID to hijack the session.
Why candidates choose this
Candidates may confuse the ability to forge tokens with the concept of fixing a session ID, as both involve an attacker controlling a session token, but the mechanisms differ.
Analysis generated from the official SY0-701blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
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Last reviewed: Jun 11, 2026
This SY0-701 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SY0-701 exam.
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