SCS-C02 Infrastructure Security Practice Question
Exhibit
Refer to the exhibit.
[ec2-user@ip-10-0-1-5 ~]$ aws ec2 describe-security-groups --group-ids sg-12345678
{
"SecurityGroups": [
{
"GroupId": "sg-12345678",
"GroupName": "web-sg",
"VpcId": "vpc-12345678",
"IpPermissions": [
{
"IpProtocol": "tcp",
"FromPort": 80,
"ToPort": 80,
"IpRanges": [
{
"CidrIp": "0.0.0.0/0"
}
]
}
],
"IpPermissionsEgress": []
}
]
}A security engineer runs the above AWS CLI command. The engineer notices that the security group has no outbound rules. What is the implication of this configuration?
⚠ Common exam trap
The trap is assuming statefulness means outbound is always allowed — statefulness only covers return traffic for established flows, not new outbound-initiated connections when no egress rule exists.
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
✓
The EC2 instances in this security group cannot initiate outbound connections
Security groups are stateful and, by default, allow all outbound traffic; however, if outbound rules are explicitly removed, the group has no rule permitting egress, so instances cannot initiate outbound connections. Return traffic for allowed inbound connections is still permitted due to statefulness, but new outbound-initiated flows are blocked. Thus the correct implication is that outbound connections cannot be initiated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The EC2 instances in this security group cannot initiate outbound connections
Why this is correct
Security groups are stateful and allow all outbound traffic by default; removing every outbound rule leaves no permit, so instances cannot initiate connections. Return traffic for inbound-initiated flows still passes, but new outbound sessions are blocked.
- ✗
The EC2 instances cannot receive inbound HTTP traffic
Why it's wrong here
Inbound HTTP depends on inbound rules, not outbound rules; absent outbound rules block traffic the instances initiate, including responses to inbound requests. It tempts those reasoning that return traffic needs an outbound rule, but security groups are stateful, so replies to permitted inbound connections are allowed regardless of outbound rules.
- ✗
The security group allows all outbound traffic by default
Why it's wrong here
AWS security groups are allow-lists with an implicit deny; a group with no outbound rules permits no outbound traffic, not all of it. The option tempts engineers recalling that newly created groups include an allow-all outbound rule, but that default rule was removed here, so egress is denied.
- ✗
Outbound traffic is allowed because security groups are stateful
Why it's wrong here
Statefulness means return traffic for permitted inbound connections is automatically allowed; it does not authorise outbound-initiated connections, which require explicit outbound rules. The option tempts engineers who know security groups track connection state, but stateful tracking applies only to responses of allowed flows, so with no outbound rules no instance-initiated egress succeeds.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SCS-C02 practice question is part of Courseiva's free Amazon Web Services 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 SCS-C02 exam.