A.　Chamoli　and　C.M.　Bhandari　presented　a　secure　direct　communication　based　on　ping-pong　protocol[Quantum　Inf.　Process.　8,　347　(2009)].　M.Naseri　analyzed　its　security　and　pointed　out　that　in　this　protocol　any　dishonest　party　can　obtain　all　the　other　one＇s　secret　message　with　zero　risk　of　being　detected　by　using　fake　entangled　particles　(FEP　attack)　[M.　Naseri,　Quantum　Inf.　Process.　online].　In　this　letter,　we　reexamine　the　protocol＇s　security　and　discover　that　except　the　FEP　attack,　using　a　special　property　of　GHZ　states,　any　one　dishonest　party　can　also　take　a　special　attack,　i.e.,　double-CNOT(Controlled　NOT)　attack.　Finally,　a　denial-of-service　attack　is　also　discussed.