The answer is SQL injection, exploited through the lack of network segregation between the web and database tiers. An attacker can inject malicious SQL commands into a web application, and because the firewall permits direct MySQL traffic from the web server to the database server without any application-layer filtering, the attacker can extract sensitive data directly from the database. The IDS on the DMZ-Internal segment only alerts on suspicious activity but does not block it, meaning the attacker’s pivot from the compromised web server to the database goes unimpeded. On the CISM exam, this scenario tests your understanding of defense-in-depth failures—specifically how a permissive firewall rule combined with a passive IDS creates a critical gap. A common trap is focusing on the IDS alerting as a safeguard, but remember: detection without prevention is not segregation. Memory tip: “SQL injection loves a direct path—if the firewall says yes and the IDS just watches, the database is exposed.”
CISM Information Security Program Practice Question
This CISM practice question tests your understanding of information security program. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Exhibit
Refer to the exhibit.
Exhibit: Network Architecture Description
The network consists of three zones: External, DMZ, and Internal. The external interface connects to the internet. The DMZ hosts public-facing web servers and an email relay. The internal zone hosts database servers and application servers. A firewall separates External from DMZ, and another firewall separates DMZ from Internal. The firewall rules are:
- External to DMZ: allow HTTP, HTTPS, SMTP.
- DMZ to Internal: allow MySQL (3306) from web servers to database servers, and allow LDAP (389) from application servers to domain controllers.
- Internal to External: allow outbound HTTP/HTTPS from application servers.
- All other traffic is denied.
The IDS is placed on the DMZ segment, monitoring traffic between DMZ and Internal. The IDS signatures include critical, high, and medium severity, and the action is 'alert and log'.
Based on the exhibit, what is the most likely vulnerability that an attacker could exploit?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Refer to the exhibit.
Exhibit: Network Architecture Description
The network consists of three zones: External, DMZ, and Internal. The external interface connects to the internet. The DMZ hosts public-facing web servers and an email relay. The internal zone hosts database servers and application servers. A firewall separates External from DMZ, and another firewall separates DMZ from Internal. The firewall rules are:
- External to DMZ: allow HTTP, HTTPS, SMTP.
- DMZ to Internal: allow MySQL (3306) from web servers to database servers, and allow LDAP (389) from application servers to domain controllers.
- Internal to External: allow outbound HTTP/HTTPS from application servers.
- All other traffic is denied.
The IDS is placed on the DMZ segment, monitoring traffic between DMZ and Internal. The IDS signatures include critical, high, and medium severity, and the action is 'alert and log'.
A
An attacker could perform a DDoS attack on the external interface to disrupt email services.
Why wrong: Possible but not the most likely vulnerability; email may have mitigation.
B
An attacker could use SQL injection on the web server to extract data directly from the database via the permitted MySQL traffic.
The MySQL rule allows direct database access from web; SQL injection can leverage this.
C
An attacker could exploit the SMTP service to send spam.
Why wrong: Spam is not a data breach; less likely as a primary exploit.
D
An attacker could sniff traffic on the DMZ segment to capture LDAP credentials.
Why wrong: LDAP is between application servers and domain controllers; not directly exploitable from external.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
An attacker could use SQL injection on the web server to extract data directly from the database via the permitted MySQL traffic.
The IDS is on the DMZ-Internal segment, but it only alerts; it does not block. If an attacker compromises a web server, they can communicate with the database server without being blocked by the IDS (only alerted). Additionally, the firewall allows MySQL direct from web to database, so after compromise, the attacker can extract data. The most likely vulnerability is the lack of network segregation between web and database tiers – they are in different zones but the firewall rule permits MySQL directly, and the IDS is passive. However, the question asks for most likely exploit: an attacker could use SQL injection to compromise the web server and then pivot to the database. The IDS may detect but not prevent. So the gap is that the database is directly accessible from the web tier without any application-layer filtering. Among options, we need to pick one that correctly identifies the exploit path.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
An attacker could perform a DDoS attack on the external interface to disrupt email services.
Why it's wrong here
Possible but not the most likely vulnerability; email may have mitigation.
✓
An attacker could use SQL injection on the web server to extract data directly from the database via the permitted MySQL traffic.
Why this is correct
The MySQL rule allows direct database access from web; SQL injection can leverage this.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
An attacker could exploit the SMTP service to send spam.
Why it's wrong here
Spam is not a data breach; less likely as a primary exploit.
✗
An attacker could sniff traffic on the DMZ segment to capture LDAP credentials.
Why it's wrong here
LDAP is between application servers and domain controllers; not directly exploitable from external.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
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
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CISM NAT questions on configuration and troubleshooting.
Information Security Program — This question tests Information Security Program — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: An attacker could use SQL injection on the web server to extract data directly from the database via the permitted MySQL traffic. — The IDS is on the DMZ-Internal segment, but it only alerts; it does not block. If an attacker compromises a web server, they can communicate with the database server without being blocked by the IDS (only alerted). Additionally, the firewall allows MySQL direct from web to database, so after compromise, the attacker can extract data. The most likely vulnerability is the lack of network segregation between web and database tiers – they are in different zones but the firewall rule permits MySQL directly, and the IDS is passive. However, the question asks for most likely exploit: an attacker could use SQL injection to compromise the web server and then pivot to the database. The IDS may detect but not prevent. So the gap is that the database is directly accessible from the web tier without any application-layer filtering. Among options, we need to pick one that correctly identifies the exploit path.
What should I do if I get this CISM question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CISM NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CISM practice question is part of Courseiva's free ISACA 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 CISM exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.