Droppers are software that phishing victims tend to be tricked into downloading and running on their system. The dropper may advertise itself as something useful or legitimate such as a codec to view a certain video or software to open a specific file.
The droppers are not usually malicious themselves, so they tend to pass antivirus checks. Once installed, the intended malware is either unpacked or downloaded from a server and installed onto the victimโs computer. The malicious software usually connects back to the attackerโs infrastructure. The attacker can take control of the victimโs computer, which can further explore and exploit the local network.