According to the NY Times:
The New York Times has verified security camera footage on Tuesday that shows, for the first time, that two missiles hit Ukraine International Airlines Flight 752 on Jan. 8. The missiles were launched from an Iranian military site around eight miles from the plane.
The new video fills a gap about why the plane’s transponder stopped working, seconds before it was hit by a second missile.
An earlier Times analysis confirmed what Iran later admitted: that an Iranian missile did strike the plane. The Times also established that the transponder stopped working before that missile hit the plane. The new video appears to confirm that an initial strike disabled the transponder, before the second strike, also seen in the video, around 23 seconds later.