There is far too much evidence contained in this report not to be true. Besides, it is supported by other credible sources in the past (see here and here). Of course, ISIS could not exist without this type of support.
A months-long investigation which tracked and exposed a massive covert weapons shipment network to terror groups in Syria via diplomatic flights originating in the Caucuses and Eastern Europe under the watch of the CIA and other intelligence agencies has resulted in the interrogation and firing of the Bulgarian journalist who first broke the story. This comes as the original report is finally breaking into mainstream international coverage.
Investigative reporter Dilyana Gaytandzhieva authored a bombshell report for Trud Newspaper, based in Sofia, Bulgaria, which found that an Azerbaijan state airline company was regularly transporting tons of weaponry to Saudi Arabia, United Arab Emirates (UAE), and Turkey under diplomatic cover as part of the CIA covert program to supply anti-Assad fighters in Syria. Those weapons, Gaytandzhieva found, ended up in the hands of ISIS and al-Qaeda terrorists in Iraq and Syria.