I was just curious if anyone else has had many false positives with 3 signatures in particular: TCP Hijack (3250.0 - High), TCP Hijack Simplex Mode (3251.0 - High), and TCP Segment Overwrite (1300.0 - High). The reason I think they are false positives is because they occur everyday, and I've also seem them caused by internal network traffic that crosses an IPS sensor (that is, making the potentially dangerous assumption that the internal devices can be trusted). We usually see between a dozen and 3 dozen a day depending on the signature, and we have 8 IPS total deployed internally and on the perimeters.
Has anyone else had similar experiences? If so, do you have any suggestions on how to decrease the number of false positives for these alerts?