čovjek s papirnatom vrećicom na glavi
Danas, nakon ažuriranja Cataline s 15.6 na 15.7, pala je brzina interneta, nešto mi je jako opterećivalo mrežu i odlučio sam pogledati mrežnu aktivnost.
Pokrenuo sam tcpdump nekoliko sati:
sudo tcpdump -k NP > ~/log
I prvo što mi je upalo u oči:
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
Zašto mu treba cijela moja lokalna mreža? Neprestano ga skenira svake minute 192.168.1./255, u redu, recimo da je ovo usluga mrežnog preglednika.
(shadowserver.org) — neprofitna sigurnosna organizacija
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
Još jedno kucalo (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
Dobro, dobro, čini se da nije ništa posebno: analitika, skeniranje lokalne mreže, dobro, uobičajena stvar, ali što s ovim:
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
Ako odete na ovu IP adresu
Tekstualne datoteke sadrže milijune IP adresa s portovima.
Sadržaj privremene datoteke:
[?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
I za kraj, hrpa nepoznatih upita:
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
Ako blokiram te domene i IP adrese u datoteci hosta, tada će u sljedećem ispisu biti iste IP podmreže, ali s različitim krajnjim adresama, a poddomene domena se mijenjaju.
Mac ne razumije masku u datoteci hosta *.example.com
Nisam shvatio kako pogledati pakete koji se prenose i koji procesi ili demoni uzrokuju te veze (imam Mac nekoliko dana), ali već je zabavno!
Izvor: www.habr.com