On 1/31/20 12:35 PM, Ed Greshko wrote:
On 2020-02-01 04:31, Samuel Sieb wrote:
> Your original post was completely clear. However, something is happening on your
network that you aren't aware of. The fact that you are getting connections from an
external IP address means that somehow there is a path from the external internet to this
computer. It's possible that another computer on your network could somehow be
routing incoming packets to the computer, but the outgoing ones have to be following the
default route to the default gateway. An interesting split routing. tcpdump (or
wireshark) will give you the mac address and if it doesn't match your gateway, you
will have to track down which computer has that mac.
And in that regard the "arp" command may be useful. That is if one is aware of
what IP addresses on
the LAN belong to what devices.
I thought about that, but it's only useful for mapping back from the MAC
address and that would only work if the computers are talking directly
using local addresses. Only the attacking computer would have an arp
entry for the target computer. If the target does not normally have any
communication with the attacker, it won't have an entry for it. If he
has access to the gateway computer, then that would more likely have an
arp entry for the attacker.
One more thing I just thought of, depending on the network structure,
the incoming packets could also be coming through the default gateway
which would be even more difficult to track down. But without the MAC
address, it's all just speculation.