On Dec 19, 2020, at 01:19, Frank Bulk <frnk...@iname.com> wrote:
Curious if someone can point me in the right direction. In the last three days our core router (Cisco 7609) has logged the following events: Dec 16 19:04:59.027 CST: %CRYPTO-4-RECVD_PKT_INV_SPI: decaps: rec'd IPSEC packet has invalid spi for destaddr=<redacted>, prot=50, spi=0xEF7ED795(4018067349), srcaddr=68.180.160.18, input interface=Vlan20 It should be noted that attackers will sometimes generate non-TCP/-UDP/-ICMP DDoS attack traffic which is intended to bypass ACLs, firewall rules, etc. which only take the more common protocols into account. They'll often pick ESP (protocol 50, AH (protocol 51), or GRE (protocol 47) in order to try & masquerade the attack traffic as legitimate VPN or tunneled traffic. And the source IPs of this attack traffic are frequently spoofed, as well. -------------------------------------------- Roland Dobbins <roland.dobb...@netscout.com>
