Common Vulnerabilities and Exposures (CVEs) are publicly disclosed cybersecurity vulnerabilities and exposures that can affect a wide range of software, hardware, and network systems. CVEs help organizations and security professionals quickly identify and address security flaws that could be exploited by attackers. By keeping track of CVEs, security teams can prioritize patches, perform targeted scans, and protect their systems against known vulnerabilities.
Understanding CVE Numbering: A CVE identifier follows a standard format: CVE-YYYY-NNNNN. The components are as follows:
- CVE: This signifies the identifier for a vulnerability or exposure.
- YYYY: The year in which the CVE was assigned or made public.
- NNNNN: A unique serial number assigned to the CVE, starting from 00001 for the first CVE in that year.
For example:
- CVE-2023-12345 refers to the 12,345th vulnerability identified in 2023.
- CVE-2024-56789 would be the 56,789th CVE identified in 2024.
CVE entries typically contain a brief description of the vulnerability, its severity (often rated with a CVSS score), potential impacts, and mitigation or patching recommendations.
Common CVE Query Methods
To check for CVE details or scan for vulnerabilities, several tools and methods can be used. Below are some tools and commands commonly used to query CVEs:
1. Nmap (Network Mapper)
Nmap is a popular tool for network discovery and security auditing, and it can also be used to detect CVEs through service version detection and vulnerability scanning.
Basic CVE Detection Example: Scan a target for known vulnerabilities associated with the services running:
> nmap -sV --script=vuln <target>
This command scans the target and checks the version of services running, then applies vulnerability scripts based on those versions to detect associated CVEs.
Example – CVE Detection on HTTP Services:
> nmap -p 80 --script=http-vuln* <target>
This command scans the HTTP service on port 80 and checks for known vulnerabilities related to web servers.
2. CURL for NVD (National Vulnerability Database)
You can use curl to query the NVD for information about CVEs directly from their API.
Basic Curl Command to Search for CVEs:
> curl -X GET "https://services.nvd.nist.gov/rest/json/cve/1.0/CVE-2023-12345"
This command will return information about CVE-2023-12345 from the National Vulnerability Database in JSON format.
Example – Search for CVE by Product: To query for vulnerabilities related to a specific software, say Apache:
> curl -X GET "https://services.nvd.nist.gov/rest/json/cves/1.0?keyword=apache"
3. CURL for CVE Details from External Sources
Besides the NVD, other public resources provide CVE information. You can query these sources similarly to get the latest vulnerability information.
Example – Querying CVE Details from a Specific API:
> curl -X GET "https://cve.circl.lu/api/CVE-2023-98765"
This would retrieve CVE details for CVE-2023-98765 from an external CVE database.
Example: Search for CVEs by Product
> curl -X GET "https://cve.circl.lu/api/search/Apache%20HTTP%20Server"
This query will return a list of CVEs related to the Apache HTTP Server.
Example: Search for CVEs by KeywordAPI Endpoint:
> curl -X GET "https://cve.circl.lu/api/search/SQL%20injection"
This query will return a list of CVEs that contain the keyword “SQL injection” in their descriptions or metadata.
4. Custom Commands for CVE Lookup
Many security tools allow you to look up CVEs directly using custom commands or APIs. For example, you could create a script that queries NVD for multiple CVEs and fetches their status.
Example Custom Script to Search for Multiple CVEs:
#!/bin/bash
cve_list=("CVE-2023-12345" "CVE-2023-98765")
for cve in "${cve_list[@]}"; do
curl -X GET "https://services.nvd.nist.gov/rest/json/cve/1.0/$cve"
done
This script loops through a list of CVEs and fetches details for each from NVD.
Example CVE Queries and Switches
Here are some examples of how you might query or use CVEs in your penetration testing workflows:
- Nmap Example – CVE Detection: Scan for vulnerabilities based on CVE data:
> nmap --script vulners -p 80,443 <target>
This script integrates with the CVE database to detect vulnerabilities based on CVE information for the target. - CURL Example – Fetch CVE Details from NVD: Retrieve specific CVE details from the NVD API:
> curl -X GET "https://services.nvd.nist.gov/rest/json/cve/1.0/CVE-2024-00001"
This command will provide detailed information about CVE-2024-00001. - Custom Command – Query CVEs by Product: Use a custom curl command to search for vulnerabilities related to a particular software or product:
> curl -X GET "https://services.nvd.nist.gov/rest/json/cves/1.0?keyword=nginx"
Summary
CVEs are an essential part of modern cybersecurity, providing standardized identifiers for vulnerabilities in software and systems. By understanding CVE numbering and utilizing common query tools like Nmap and CURL, security professionals can efficiently monitor, identify, and patch vulnerabilities. Automated tools and custom scripts enable the seamless integration of CVE lookup into vulnerability scanning processes, ensuring that known risks are mitigated in a timely manner.