Microsoft, Mozilla Fix Five Year Old Defender Bug That Increased CPU Usage – Computer – News

Microsoft has labored with Mozilla to repair a bug in Home windows Defender that might trigger Firefox to make use of abnormally excessive CPU utilization. Hanging concerning the bug was that it was already reported 5 years in the past for Home windows 10.

The bug already appeared in Could 2018 offered in Mozilla’s bug tracker Bugzilla. The issue was named there for Home windows 10 on the time. In keeping with the reporter, the bug in some instances prompted excessive CPU consumption when Firefox was opened. That turned out to be as a consequence of Home windows Defender.

Final month programmers at Mozilla found the reason for the issue. That was in Home windows Defender’s Antimalware Service Executable, which runs as Msmpeng.exe. That executable addresses the Occasion Tracing for Home windows. Because of this, a excessive variety of VirtualProtect calls had been created whereas utilizing Defender, which prompted the CPU consumption to shoot via the roof. That might be far more widespread than with Edge, Chrome, and different browsers. Mozilla partially mitigated the bug by disabling JIT within the browser, but additionally engaged Microsoft to repair the problem, which in the end seemed to be in Defender.

Microsoft has the issue now resolved. Final week this was up to date within the Defender engine to model 1.1.20200.4 and this has now additionally occurred in Platform model 4.18.2302.x. With the latter, the detection can also be rolled out to instruments equivalent to Defender Firewall, ATP or Endpoint. The repair works for all variations of Home windows, so not solely 11 but additionally 10 and even 7 and eight.1.