CompTIA Security+ Exam Prep

Answer: B - A virus that antivirus programs cannot find due to a false image being presented to it is a stealth virus. A stealth virus hides the modifications it has made to files or boot records. This can be accomplished by monitory system functions used to read file or sectors and forging the results. This means that when an antivirus program attempts to read an infected file or sector, the original uninfected file will be presented instead of the actual infected form. The virus can hide itself by masking the size of the file it is hidden in or actually moves itself temporarily to another location while an antivirus program is carrying out its scanning process.