Security professionals are regularly identifying vulnerabilities. Vulnerabilities are weaknesses, and by reducing vulnerabilities, you can reduce risks. That sounds simple enough. However, how do you identify the vulnerabilities that represent the greatest risks? If you’re planning to take the Security+ exam, these are concepts you should understand.
Can you answer this sample question?
Q. You recently completed a vulnerability scan on your network. It reported that several servers are missing key operating system patches. However, after checking the servers, you’ve verified the servers have these patches installed. Which of the following BEST describes this?
A. False negative
B. Misconfiguration on servers
C. False positive
D.Servers not hardened
More, do you know why the correct answer is correct and the incorrect answers are incorrect? The answer and explanation is available at the end of this post.
Vulnerability Assessment
The overall goal of a vulnerability assessment is to assess the security posture of systems and networks. They identify vulnerabilities, or weaknesses, within systems, networks, and organizations, and are part of an overall risk management plan.
Vulnerability assessments can include information from a wide variety of sources. This includes reviewing security policies and logs, interviewing personnel, and testing systems. Assessments often use vulnerability scans and penetration tests. A vulnerability assessment often includes the following high-level steps:
- Identify assets and capabilities.
- Prioritize assets based on value.
- Identify vulnerabilities and prioritize them.
- Recommend controls to mitigate serious vulnerabilities.
Many organizations perform vulnerability assessments internally. Organizations also occasionally hire external security professionals to complete external assessments.
Remember this
A vulnerability assessment determines the security posture of a system or network by identifying vulnerabilities and weaknesses. Assessments include the results of various tools, such as vulnerability scanners, audits, and reviews.
Identifying Vulnerabilities
At this stage, attackers know the IP address of live systems, what operating systems they’re running, and what protocols they’re running. This information is passed to the appropriate experts. For example, some attackers may be experts at attacking IIS web servers and Windows systems, while others are experts at attacking Apache web servers and Linux or Unix systems.
If it’s a web server, attackers may check to see if input validation techniques are in place. If not, it may be susceptible to buffer overflow, command injection, SQL injection, or cross-site scripting attacks. If it’s an application server with known default accounts and passwords, the attacker checks to see if the defaults are still available.
Many vulnerability scanners can easily check for current patches. If systems aren’t kept up to date with current patches, they are susceptible to known vulnerabilities. Again, vulnerability scanners can identify vulnerabilities, and both security professionals and attackers can use them.
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Attack Tools
Attackers now have a list of systems and their vulnerabilities. They may have attack tools they can run immediately to exploit vulnerable systems. Other times, experts may write code to exploit a new vulnerability. However, you can bet that they will attack.
The reconnaissance and fingerprinting stages may take days, weeks, or months. Some attacks are quick after some detailed planning, whereas other attacks linger as long as the attacker is undetected or until the attacker has completed the mission.
For example, when attackers extract or exfiltrate data, they often get in and get out as soon as possible. This often requires them to use privilege escalation tactics to gain elevated rights and permissions to access the data. Escalating their privileges is likely to sound an alarm. Once they’re detected, they can expect to be blocked, so they must get as much data as possible, as quickly as possible. However, sometimes the attacks are undetected, and they can continue the attacks for days.
It’s also worth pointing out that attackers often launch attacks through other systems. They take control of remote computers through different types of malware and launch the attacks through these systems. It is difficult, though not impossible, to track these attacks back to the actual source.
As the last step in the attack, many attackers attempt to erase or modify the logs. The goal is to remove traces of their attack.
False Positive
Unfortunately, vulnerability scanners aren’t perfect. Occasionally, they report a vulnerability when it doesn’t actually exist. In other words, the scan reports a positive on a known vulnerability, but the report is false. As an example, a vulnerability scan on a server might report that the server is missing patches related to a database application, but the server doesn’t have a database application installed.
This is similar to false positives in an intrusion detection system (IDS) where the IDS alerts on an event, but the event isn’t an actual intrusion. Similarly, an antivirus scanner can identify a useful application as malware, even though the application does not have any malicious code. False positives can result in higher administrative overhead because administrators have to investigate them.
Remember this
A false positive from a vulnerability scan indicates the scan detected a vulnerability, but the vulnerability doesn’t actually exist.
Q. You recently completed a vulnerability scan on your network. It reported that several servers are missing key operating system patches. However, after checking the servers, you’ve verified the servers have these patches installed. Which of the following BEST describes this?
A. False negative
B. Misconfiguration on servers
C. False positive
D.Servers not hardened
Answer is C. In this scenario, the vulnerability scanner reported a false positive indicating that the servers had a vulnerability, but in reality, the servers did not have the vulnerability.
A false negative occurs if a vulnerability scanner does not report a known vulnerability.
There isn’t any indication that the servers are misconfigured and they are not hardened.
