ProHoster > Blog > Administration > I looked at my traffic: he knew everything about me (Mac OS Catalina)

I looked at my traffic: he knew everything about me (Mac OS Catalina)

I looked at my traffic: he knew everything about me (Mac OS Catalina)man with a paper bag on his head

Today, after updating Catalina from 15.6 to 15.7, the Internet speed dipped, something heavily loaded my network and I decided to look at network activity.

Ran tcpdump for a couple of hours:

sudo tcpdump -k NP > ~/log

And the first thing that caught my eye:

16:43:42.919443 () ARP, Request who-has 192.168.1.51 tell 192.168.1.1, length 28
16:43:42.927716 () ARP, Request who-has 192.168.1.52 tell 192.168.1.1, length 28
16:43:42.934112 () ARP, Request who-has 192.168.1.53 tell 192.168.1.1, length 28
16:43:42.942328 () ARP, Request who-has 192.168.1.54 tell 192.168.1.1, length 28
16:43:43.021971 () ARP, Request who-has 192.168.1.55 tell 192.168.1.1, length 28

Why does he need my entire local network? It scans it endlessly every minute 192.168.1./255, okay, let's say this is a network browser service.

(shadowserver.org) is a non-profit security organization

16:43:33.518282 () IP scan-05l.shadowserver.org.33567 > 192.168.1.150.rsync: Flags [S], seq 1527048226, win 65535, options [mss 536], length 0

Another snitch (scanner-12.ch1.censys-scanner.com -> censys.io):

16:44:16.254073 () IP scanner-12.ch1.censys-scanner.com.62651 > 192.168.1.150.8843: Flags [S], seq 1454862354, win 1024, options [mss 1460], length 0

Okay, okay, it seems nothing special: analytics, scanning the local network, well, the usual thing, but then what is this:

16:15:56.603292 () IP 45.129.33.152.51777 > 192.168.1.150.jpegmpeg: Flags [S], seq 2349838714, win 1024, options [mss 536], length 0

If you go to this ip address http://45.129.33.152, you can see this:

I looked at my traffic: he knew everything about me (Mac OS Catalina)Text files contain millions of ip addresses with ports.

Contents of the temp file:

[?1h=[?25l[H[J[mtop - 21:17:26 up 31 days,  6:44,  1 use[m[39;49m[m[39;49m[K
Tasks:[m[39;49m[1m 144 [m[39;49mtotal,[m[39;49m[1m   1 [m[39;49mrunning,[m[39;49m[1m 143 [m[39;49msleep[m[39;49m[m[39;49m[K
%Cpu(s):[m[39;49m[1m  0.8 [m[39;49mus,[m[39;49m[1m  0.0 [m[39;49msy,[m[39;49m[1m  0.0 [m[39;49mni,[m[39;49m[1m 92.0[m[39;49m[m[39;49m[K
KiB Mem :[m[39;49m[1m 32681700 [m[39;49mtotal,[m[39;49m[1m 18410244 [m[39;49mfree,[m[39;49m[m[39;49m[K
KiB Swap:[m[39;49m[1m 16449532 [m[39;49mtotal,[m[39;49m[1m 16449288 [m[39;49mfree,[m[39;49m[m[39;49m[K
[K
[7m  PID USER      PR  NI    VIRT    RES [m[39;49m[K
[m    1 root      20   0  191072   3924 [m[39;49m[K
[m    2 root      20   0       0      0 [m[39;49m[K
[m    3 root      20   0       0      0 [m[39;49m[K
[m    5 root       0 -20       0      0 [m[39;49m[K
[m    7 root      rt   0       0      0 [m[39;49m[K
[m    8 root      20   0       0      0 [m[39;49m[K
[m    9 root      20   0       0      0 [m[39;49m[K
[m   10 root      rt   0       0      0 [m[39;49m[K
[m   11 root      rt   0       0      0 [m[39;49m[K
[m   12 root      rt   0       0      0 [m[39;49m[K
[m   13 root      20   0       0      0 [m[39;49m[K
[m   15 root       0 -20       0      0 [m[39;49m[K
[m   16 root      rt   0       0      0 [m[39;49m[K[H[mtop - 21:17:29 up 31 days,  6:44,  1 use[m[39;49m[m[39;49m[K

%Cpu(s):[m[39;49m[1m  0.0 [m[39;49mus,[m[39;49m[1m  0.0 [m[39;49msy,[m[39;49m[1m  0.0 [m[39;49mni,[m[39;49m[1m100.0[m[39;49m[m[39;49m[K
KiB Mem :[m[39;49m[1m 32681700 [m[39;49mtotal,[m[39;49m[1m 18409876 [m[39;49mfree,[m[39;49m[m[39;49m[K

[K

And finally, a bunch of unknown requests:

16:16:07.022910 () IP 059148253194.ctinets.com.58703 > 192.168.1.150.4244: Flags [S], seq 2829545743, win 1024, options [mss 536], length 0
16:15:57.133836 () IP 45.129.33.2.55914 > 192.168.1.150.39686: Flags [S], seq 700814637, win 1024, options [mss 536], length 0
16:15:56.603292 () IP 45.129.33.152.51777 > 192.168.1.150.jpegmpeg: Flags [S], seq 2349838714, win 1024, options [mss 536], length 0
16:16:15.083755 () IP 45.129.33.154.55846 > 192.168.1.150.7063: Flags [S], seq 4079154719, win 1024, options [mss 536], length 0
16:15:43.251305 () IP 192.168.1.150.60314 > one.one.one.one.domain: 3798+ PTR? 237.171.154.149.in-addr.arpa. (46)
16:16:24.386628 () IP 45.141.84.30.50763 > 192.168.1.150.12158: Flags [S], seq 572523718, win 1024, options [mss 536], length 0
16:16:44.817035 () IP 92.63.197.66.58219 > 192.168.1.150.15077: Flags [S], seq 4012437618, win 1024, options [mss 536], length 0
16:15:43.172042 () IP 45.129.33.46.51641 > 192.168.1.150.bnetgame: Flags [S], seq 362771723, win 1024, options [mss 536], length 0
16:17:02.120063 () IP 45.129.33.23.42275 > 192.168.1.150.11556: Flags [S], seq 3354007029, win 1024, options [mss 536], length 0
16:16:00.589816 () IP 45.129.33.3.56005 > 192.168.1.150.40688: Flags [S], seq 2710391040, win 1024, options [mss 536], length 0

If I block these domains and ip addresses in the host file, then the next dump will have the same ip subnets, but with different end addresses, and the domains change subdomain.

Mac doesn't understand mask in host *.example.com file

How to see the packets that are being transmitted and what processes or daemons are causing these connections, I have not yet figured out (I have a poppy for several days), but already fun!

Source: habr.com