Malware
Malware (a portmanteau for malicious software) is any software intentionally designed to cause damage to a computer, server, client, or computer network. Malware does the damage after it is implanted or introduced in some way into a target's computer and can take the form of executable code, scripts, active content, and other software. The code is described as computer viruses, worms, Trojan horses, ransomware, spyware, adware, and scareware, among other terms. Malware has a malicious intent, acting against the interest of the computer user—and so does not include software that causes unintentional harm due to some deficiency, which is typically described as a software bug.
Watering hole attack
From August to September 2017 the installation binary of Ccleaner distributed by the vendor's download servers included malware. Ccleaner is a popular tool used to clean potentially unwanted files from Windows computers, widely used by security-minded users. The distributed installer binaries were signed with the developer's certificate making it likely that an attacker compromised the development or build environment and used this to insert malware.