An adversary may rely upon a user clicking a malicious link in order to gain execution. Users may be subjected to social engineering to get them to click on a link that will lead to code execution. This user action will typically be observed as follow-on behavior from Spearphishing Link. Clicking on a link may also lead to other execution techniques such as exploitation of a browser or application vulnerability via Exploitation for Client Execution. Links may also lead users to download files that require execution via Malicious File.
|C0022||Operation Dream Job|
|C0016||Operation Dust Storm|
TA505 has used lures to get users to click links in emails and attachments. For example, TA505 makes their malware look like legitimate Microsoft Word documents, .pdf and/or .lnk files. 
|M1031||Network Intrusion Prevention||
If a link is being visited by a user, network intrusion prevention systems and systems designed to scan and remove malicious downloads can be used to block activity.
|M1021||Restrict Web-Based Content||
If a link is being visited by a user, block unknown or unused files in transit by default that should not be downloaded or by policy from suspicious sites as a best practice to prevent some vectors, such as .scr, .exe, .pif, .cpl, etc. Some download scanning devices can open and analyze compressed and encrypted formats, such as zip and rar that may be used to conceal malicious files.
Use user training as a way to bring awareness to common phishing and spearphishing techniques and how to raise suspicion for potentially malicious events.
|ID||Data Source||Data Component||Detects|
malicious documents and files that are downloaded from a link and executed on the user's computer
|DS0029||Network Traffic||Network Connection Creation||
Monitor for newly constructed web-based network connections that are sent to malicious or suspicious destinations (e.g. destinations attributed to phishing campaigns). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments (e.g. monitor anomalies in use of files that do not normally initiate network connections or unusual connections initiated by regsvr32.exe, rundll.exe, .SCF, HTA, MSI, DLLs, or msiexec.exe).
|Network Traffic Content||
Monitor and analyze traffic patterns and packet inspection associated with web-based network connections that are sent to malicious or suspicious detinations (e.g. destinations attributed to phishing campaigns). Consider correlation with process monitoring and command line to detect anomalous processes execution and command line arguments (e.g. monitor anomalies in use of files that do not normally initiate network connections or unusual connections initiated by regsvr32.exe, rundll.exe, .SCF, HTA, MSI, DLLs, or msiexec.exe).