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.
Stegomalware
The term of `stegomalware' was introduced by researchers in the context of mobile malware and presented at Inscrypt conference in 2014. However, the fact that (mobile) malware could potentially utilize steganography was already presented in earlier works: the use of steganography in malware was first applied to botnets communicating over probabilistically unobservable channels, mobile malware based on covert channels was proposed in the same year. Steganography was later applied to other components of malware engineering such as return-oriented programming and compile-time obfuscation, among others.