[tor-relays] What're these ufw block logs saying?

Mailing Lists tor-relays
1

Hi,

re. my (guard / middle relay) : 181.215.226.65 : 443 : http://hctxrvjzfpvmzh2jllqhgvvkoepxb4kfzdjm6h7egcwlumggtktiftid.onion/rs.html#details/41D4F82AB54AE5C5FB8D3CD24B4FC84350EFEF03

I’m getting traffic from another (non-exit) relay : 155.138.146.249 : 9001 : http://hctxrvjzfpvmzh2jllqhgvvkoepxb4kfzdjm6h7egcwlumggtktiftid.onion/rs.html#details/87EBD436D6EC7E2A83AC1CAAF46B44CFF15CDCA8 ( CCed)

always from port 9001 but to different, high number destination (on my vps) ports which ufw is blocking.
This isn’t Tor traffic I’m blocking, right? That would only come to my ORport? Is this abuse attempts? Under the cover of Tor relay traffic? They’re quite infrequent (sample) :

Dec 23 14:33:29 xxxxxxxx kernel: [2228957.705152] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=37256 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:33:34 xxxxxxxx kernel: [2228962.788380] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=37256 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:52:36 xxxxxxxx kernel: [2230104.586835] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:53:16 xxxxxxxx kernel: [2230144.487410] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:53:54 xxxxxxxx kernel: [2230183.086653] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:16:42 xxxxxxxx kernel: [2231550.336547] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=40 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=0 RES=0x00 ACK RST URGP=0

Dec 23 15:18:15 xxxxxxxx kernel: [2231644.112246] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:22:31 xxxxxxxx kernel: [2231900.117391] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=52 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=0 RES=0x00 ACK RST URGP=0

Dec 23 15:42:30 xxxxxxxx kernel: [2233098.835686] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:43:34 xxxxxxxx kernel: [2233162.852181] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:45:42 xxxxxxxx kernel: [2233290.874044] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=0 RES=0x00 ACK PSH RST URGP=0

Dec 23 16:14:43 xxxxxxxx kernel: [2235032.148940] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=1124 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=47586 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Thanks,

Pete

2

Hello,

this is weird indeed, but the packet size is interesting.

For example, using the tool MTR, you can trace the route to another host using different protocols:

1.) ICMP being the obvious default.
2.) TCP.
3.) UDP.

If all these TCP packets were just below 100 bytes, that would be my guess.

Looking up the relay, there is a name, e-mail contact and PGP key ID for this node operator:

"Tom"
tom@kh6ilt.org
0x620836CF

Just ask this operator first to check his server for something that could cause this, and if he is running something special alongside Tor.

Then, if that does not sufficiently explain or resolve the spurious packets, I would recommend to install tcpdump, and to use a syntax like:

sudo tcpdump tcp and src host 155.138.146.249 and not dst port 443 -w dump.pcap

You will need elevated privileges in order to run tcpdump.

This will _guarantee_ to exclude all legitimate Tor traffic originating from his server by excluding destination port 443, and log the remaining packets to file "dump.pcap".

You can add the -i <interface> parameter to the beginning of the tcpdump argument list if you have multiple public interfaces.

Like so:

tcpdump -i eth0 <other arguments>

Once the dump is finished, you can send signal 2 / SIGINT if the process is running in the background, or simply press CTRL + C.. both ways lead to a graceful exit of tcpdump:

kill --signal 2 tcpdump

Now you can inspect the traffic using a GUI tool like Wireshark (highly recommended) which can parse .pcap files and decode / recognize many types of packets.

Please report back what you find!

All the best,
-GH

···

On Monday, December 23rd, 2024 at 6:46 PM, code9n via tor-relays <tor-relays@lists.torproject.org> wrote:

Hi,

re. my (guard / middle relay) : 181.215.226.65 : 443 : http://hctxrvjzfpvmzh2jllqhgvvkoepxb4kfzdjm6h7egcwlumggtktiftid.onion/rs.html#details/41D4F82AB54AE5C5FB8D3CD24B4FC84350EFEF03

I'm getting traffic from another (non-exit) relay : 155.138.146.249 : 9001 : http://hctxrvjzfpvmzh2jllqhgvvkoepxb4kfzdjm6h7egcwlumggtktiftid.onion/rs.html#details/87EBD436D6EC7E2A83AC1CAAF46B44CFF15CDCA8 ( CCed)

always from port 9001 but to different, high number destination (on my vps) ports which ufw is blocking.
This isn't Tor traffic I'm blocking, right? That would only come to my ORport? Is this abuse attempts? Under the cover of Tor relay traffic? They're quite infrequent (sample) :

Dec 23 14:33:29 xxxxxxxx kernel: [2228957.705152] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=37256 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:33:34 xxxxxxxx kernel: [2228962.788380] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=37256 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:52:36 xxxxxxxx kernel: [2230104.586835] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:53:16 xxxxxxxx kernel: [2230144.487410] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 14:53:54 xxxxxxxx kernel: [2230183.086653] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=55546 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:16:42 xxxxxxxx kernel: [2231550.336547] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=40 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=0 RES=0x00 ACK RST URGP=0

Dec 23 15:18:15 xxxxxxxx kernel: [2231644.112246] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:22:31 xxxxxxxx kernel: [2231900.117391] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=52 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=40998 WINDOW=0 RES=0x00 ACK RST URGP=0

Dec 23 15:42:30 xxxxxxxx kernel: [2233098.835686] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:43:34 xxxxxxxx kernel: [2233162.852181] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Dec 23 15:45:42 xxxxxxxx kernel: [2233290.874044] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=588 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=32822 WINDOW=0 RES=0x00 ACK PSH RST URGP=0

Dec 23 16:14:43 xxxxxxxx kernel: [2235032.148940] [UFW BLOCK] IN=eth0 OUT= MAC=00:16:3e:b0:d2:70:e4:5d:37:86:2c:2c:08:00 SRC=155.138.146.249 DST=181.215.226.65 LEN=1124 TOS=0x00 PREC=0x00 TTL=55 ID=0 DF PROTO=TCP SPT=9001 DPT=47586 WINDOW=1027 RES=0x00 ACK PSH URGP=0

Thanks,

Pete