Reports from early 2007 indicated that WSR is vulnerable to attackers using speech recognition for malicious operations by playing certain audio commands through a target's speakers; it was the first vulnerability discovered after Windows Vista's general availability. Microsoft stated that although such an attack is theoretically possible, a number of mitigating factors and prerequisites would limit its effectiveness or prevent it altogether: a target would need the recognizer to be active and configured to properly interpret such commands; microphones and speakers would both need to be enabled and at sufficient volume levels; and an attack would require the computer to perform visible operations and produce audible feedback without users noticing. User Account Control would also prohibit the occurrence of privileged operations.