tor-relays November 2017

tor-relays@lists.torproject.org

54 participants
41 discussions

ansible-relayor, how to ?
by Petrusko 01 Apr '18

01 Apr '18

Hey! I'm planning to try the "ansible-relayor" to deploy some Tor relay instances. If I'm not wrong, it's a main goal ? 2 instances / IP... (soooory for being really noob about this!!!) But I'm lost... not found a tutorial, step by step, you know the tutorial so loved by all noobs! For now, on a fresh Debian8 install, there are : - tor 0.2.9.8 (fresh install from depo, client is ok when opening log file) - ansible - ansible-galaxy install nusenu.relayor - git clone https://github.com/nusenu/ansible-relayor (the folder is stored in my /home...) Will it configure (automatically) many torrc file per instance ? +every key files /relay ? (I'm not too much lost!) Do have I to do this install on every server built ? Or relayor can manage few servers on different locations ? Command lines list use this tool if available ? Many thx for help !!! (and hard work for this tool :) -- Petrusko C0BF 2184 4A77 4A18 90E9 F72C B3CA E665 EBE2 3AE5

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Decline in relays
by David Goulet 26 Dec '17

26 Dec '17

Hello everyone! Since July 2017, there has been a steady decline in relays from ~7k to now ~6.5k. This is a bit unusual that is we don't see often such a steady behavior of relays going offline (at least that I can remember...). It could certainly be something normal here. However, we shouldn't rule out a bug in tor as well. The steadyness of the decline makes me a bit more worried than usual. You can see the decline has started around July 2017: https://metrics.torproject.org/networksize.html?start=2017-06-01&end=2017-1… What happened around July in terms of tor release: 2017-06-08 09:35:17 -0400 802d30d9b7 (tag: tor-0.3.0.8) 2017-06-08 09:47:44 -0400 e14006a545 (tag: tor-0.2.5.14) 2017-06-08 09:47:58 -0400 aa89500225 (tag: tor-0.2.9.11) 2017-06-08 09:55:28 -0400 f833164576 (tag: tor-0.2.4.29) 2017-06-08 09:55:58 -0400 21a9e5371d (tag: tor-0.2.6.12) 2017-06-08 09:56:15 -0400 3db01d3b56 (tag: tor-0.2.7.8) 2017-06-08 09:58:36 -0400 64ac28ef5d (tag: tor-0.2.8.14) 2017-06-08 10:15:41 -0400 dc47d936d4 (tag: tor-0.3.1.3-alpha) ... 2017-06-29 16:56:13 -0400 fab91a290d (tag: tor-0.3.1.4-alpha) 2017-06-29 17:03:23 -0400 22b3bf094e (tag: tor-0.3.0.9) ... 2017-08-01 11:33:36 -0400 83389502ee (tag: tor-0.3.1.5-alpha) 2017-08-02 11:50:57 -0400 c33db290a9 (tag: tor-0.3.0.10) Note that on August 1st 2017, 0.2.4, 0.2.6 and 0.2.7 went end of life. That being said, I don't have an easy way to list which relays went offline during the decline (since July basically) to see if a common pattern emerges. So few things. First, if anyone on this list noticed that their relay went off the consensus while still having tor running, it is a good time to inform this thread :). Second, anyone could have an idea of what possibly is going on that is have one or more theories. Even better, if you have some tooling to try to list which relays went offline, that would be _awesome_. Third, knowing what was the state of packaging in Debian/Redhat/Ubuntu/... around July could be useful. What if a package in distro X is broken and the update have been killing the relays? Or something like that... Last, looking at the dirauth would be a good idea. Basically, when did the majority switched to 030 and then 031. Starting in July, what was the state of the dirauth version? Any help is very welcome! Again, this decline could be from natural cause but for now I just don't want to rule out an issue in tor or packaging. Cheers! David -- HiTVizeJUSe9JPvs6jBv/6i8YFvEYY/NZmNhD2UixVY=

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do the 800+ UbuntuCore relays constitute a Sybil attack?
by starlight.2017q4＠binnacle.cx 01 Dec '17

01 Dec '17

The population of these has been climbing for more than a week and no-one has commented, which seems odd. No contact provided. https://atlas.torproject.org/#search/UbuntuCore

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Tor security releases coming tomorrow
by Nick Mathewson 30 Nov '17

30 Nov '17

I'm sending this message to announce that we will be releasing new stable and versions of Tor tomorrow, to fix 5 security bugs. I apologise for the short notice; we've had to move up our intended release date in order to try to match with release deadlines for downstream projects. We have classified 3 of these bugs as Medium and 2 as High, per draft security process at https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/Securit… . The most serious bugs are a pair of denial-of-service issues, which we treat as high security because of the possibility of escalating them for traffic-analysis purposes. Note that only the following series are supported, and only they will receive updates: 0.2.5, 0.2.8, 0.2.9, 0.3.0, 0.3.1, and 0.3.2. 0.2.8 and 0.3.0 will become unsupported in January; 0.2.5 will become unsupported in May. best wishes, -- Nick

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Screening DNS
by Dr Gerard Bulger 29 Nov '17

29 Nov '17

The DNS 9.9.9.9 https://www.theregister.co.uk/2017/11/20/quad9_secure_private_dns_resolver/ At least is not blocking my exit node IP, simply because it is TOR! Nice. So far. Gerry

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ymkeo offline
by René Ladan 28 Nov '17

28 Nov '17

Hi, due to hardware problems my node ymkeo 4E8CE6F5651E7342C1E7E5ED031E82078134FB0D will be offline for an undetermined amount of time. René

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Re: [tor-relays] Detecting Network Attack [re: exit synflooded]
by Dhalgren Tor 26 Nov '17

26 Nov '17

>Well, it's still going on, and is pretty much ruining Libero :( . Running CentOS 6, here. > >When it's happening it can look like this: > ># netstat -n | grep -c SYN >17696 I run a fast exit and can offer some advice: 1) mitigate bug #18580 (also #21394); is a DNS denial-of-service and could be the problem. either upgrade to 0.3.2.4+ or edit resolve.conf per https://trac.torproject.org/projects/tor/wiki/doc/DnsResolver#Tuningeventdn… also check out https://arthuredelstein.net/exits/ 2) if you continue to experience excessive outbound scanning SYNs, I've found that simply enabling connection tracking helps by implicitly limiting the rate a which connections can originate. If an iptables "-m state --state ESTABLISHED,RELATED -j ACCEPT" rule exists it will turn it on or you could modprobe the module if you don't want to configure incoming connection rules. some useful sysctl.conf changes, run sysctl -p after or reboot # Tor Exit tuning. net.ipv4.ip_local_port_range = 1025 65535 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_max_tw_buckets = 4194304 net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_fin_timeout = 30 net.ipv4.tcp_keepalive_time = 300 net.ipv4.tcp_keepalive_intvl = 10 net.ipv4.tcp_keepalive_probes = 3 net.netfilter.nf_conntrack_tcp_timeout_established = 1000 net.netfilter.nf_conntrack_checksum = 0 you might see many messages: kernel: nf_conntrack: table full, dropping packet which indicates no connection table slots were available for an outbound connection and that rate limiting is effected state of connection tracking appears in /proc/net/nf_conntrack

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Re: [tor-relays] Pretty sure our exit was being synflooded
by tor＠t-3.net 26 Nov '17

26 Nov '17

I spoke too soon, it seems - the exit is struggling again, with some time spent destroyed today. As I look at what it's doing, it's clear that someone is relaying SYN packets to random ports and also random destination addresses that aren't even alive. The destination hosts and ports continually vary - it never hits multiple destinations on 1 port, and it does not hit multiple ports on 1 host. I presume it is an attack that is intended to degrade this relay's service quality, or otherwise more broadly, degrade Tor. I'm going to reject a few more trojan listen ports, it might help but it isn't a real fix. My thought btw was for Tor to rate-limit syn scanning activity between the client and the first onion router, with the function taking place in that first-hop router, not at the exit.

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Re: [tor-relays] Pretty sure our exit was being synflooded
by tor＠t-3.net 26 Nov '17

26 Nov '17

Thanks for the configuration suggestions. I intentionally set the conntrack limit high, maybe that was not the best thing. I think I'll be putting it back. Removing my extra IPTables code plus adding a reject for :8888 has made the exit behave properly again. I wonder if the best possible course of action for this sort of thing would be within Tor itself. I don't know that it was a single client connection into Tor that was causing all this trouble, but maybe it was. One would think that one client should not be allowed to do something so severe with the TCP that it can single-handedly ruin a fast exit. Maybe a code change that forces a rate-limit that significantly slows down the ability of a single client to roll port scans should be considered by the devs.

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Re: [tor-relays] Detecting Network Attack [re: exit synflooded]
by tor＠t-3.net 26 Nov '17

26 Nov '17

Well, it's still going on, and is pretty much ruining Libero :( . Running CentOS 6, here. Actually, I think from what I'm seeing that it may not exactly be a synflood targeting Libero. I think Libero may be being (ab)used to do massive portscanning or similar. Image should be visible below - it's normal statistics for the 18th through say, part of the 21st, messed up 22ed - 24th and on the 24th me trying different things in an attempt to mitigate (graph is from yesterday). Look at the SYN_SENT2 maximum. When it's happening it can look like this: # netstat -n | grep -c SYN 17696 # Also one tiny part of the netstat looked like this: tcp 0 1 64.113.32.29:33354 <external IP munged>:81 SYN_SENT tcp 0 1 64.113.32.29:39659 <external IP munged>:8888 SYN_SENT tcp 0 1 64.113.32.29:44247 <external IP munged>:87 SYN_SENT tcp 0 1 64.113.32.29:42038 <external IP munged>:8888 SYN_SENT tcp 0 1 64.113.32.29:42077 <external IP munged>:83 SYN_SENT tcp 0 1 64.113.32.29:36282 <external IP munged>:8888 SYN_SENT tcp 0 1 64.113.32.29:46023 <external IP munged>:8888 SYN_SENT Port 8888 is supposedly opened up for listen by a virus.

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tor-relays November 2017