Quick Answer
The correct answers are overly permissive IAM roles assigned to the function and event injection via malformed input. Overly permissive IAM roles are a critical serverless security concern because AWS Lambda functions often inherit broad permissions to interact with other services, and if an attacker compromises the function, they can leverage those excessive privileges to escalate access or exfiltrate data. Event injection via malformed input is equally specific to serverless architectures: since Lambda functions are triggered by events from sources like API Gateway or S3, an attacker can craft malicious input that exploits the function’s event-handling logic, leading to unintended execution paths or data corruption—a risk distinct from traditional injection attacks because the event structure itself can be manipulated to bypass validation. On the CompTIA SecurityX CAS-004 exam, this topic tests your understanding of the shared responsibility model in serverless environments and the unique attack surfaces introduced by event-driven execution. A common trap is confusing general cloud security issues (like insecure APIs) with those that are architecturally specific to serverless functions. Memory tip: think “Lambda Loot” – Lambda’s Least-privilege IAM and Input validation are your two must-check defenses.
This CAS-004 practice question tests your understanding of application environment, configuration and security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is adopting a serverless architecture using AWS Lambda. Which of the following are security concerns specific to serverless functions? (Select TWO.)
Insecure deserialization of function input
Why wrong: A general web vulnerability, not specific to serverless.
Container escape vulnerabilities
Why wrong: Serverless functions run in isolated containers, but escape is more relevant to traditional containers.
SQL injection in the database
Why wrong: A general web vulnerability, not specific to serverless.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Event injection via malformed input
Event injection via malformed input (B) is a specific serverless security concern because AWS Lambda functions are triggered by events from sources like API Gateway, S3, or DynamoDB Streams. An attacker can craft malicious input that exploits the function's event-handling logic, leading to unintended execution paths or data corruption. This differs from traditional injection attacks because the event structure itself can be manipulated to bypass validation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Insecure deserialization of function input
Why it's wrong here
A general web vulnerability, not specific to serverless.
Container escape vulnerabilities
Why it's wrong here
Serverless functions run in isolated containers, but escape is more relevant to traditional containers.
SQL injection in the database
Why it's wrong here
A general web vulnerability, not specific to serverless.
Option-by-option analysis
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The CAS-004 exam frequently reuses these exact scenarios with slightly different constraints.
Why this is wrong here
A general web vulnerability, not specific to serverless.
Why this is wrong here
Serverless functions run in isolated containers, but escape is more relevant to traditional containers.
Why this is wrong here
A general web vulnerability, not specific to serverless.
Analysis generated from the official CAS-004blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Common exam traps
CompTIA often tests the misconception that serverless functions are immune to injection attacks because they are 'stateless' or 'event-driven,' but the trap here is that event injection is a distinct attack vector where the event structure itself is the injection surface, not just the data within it.
Detailed technical explanation
AWS Lambda functions run in a Firecracker microVM, which provides stronger isolation than containers by using a minimal KVM-based virtual machine; this prevents container escape attacks but introduces event injection risks because the function's execution context is entirely driven by the incoming event payload. A real-world scenario is a Lambda function that processes S3 object creation events: an attacker could upload a file with a crafted key that includes path traversal sequences (e.g., '../'), causing the function to read or write to unintended S3 prefixes. Under the hood, the event is a JSON object parsed by the Lambda runtime, and if the function lacks input validation, the attacker can inject arbitrary keys or values that alter control flow.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
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FAQ
Application Environment, Configuration and Security — This question tests Application Environment, Configuration and Security — Read the scenario before looking for a memorised answer..
The correct answer is: Event injection via malformed input — Event injection via malformed input (B) is a specific serverless security concern because AWS Lambda functions are triggered by events from sources like API Gateway, S3, or DynamoDB Streams. An attacker can craft malicious input that exploits the function's event-handling logic, leading to unintended execution paths or data corruption. This differs from traditional injection attacks because the event structure itself can be manipulated to bypass validation.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 30, 2026
This CAS-004 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 CAS-004 exam.
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