Threat Level: green Handler on Duty: Johannes Ullrich

SANS ISC: InfoSec Handlers Diary Blog - Internet Storm Center Diary 2017-10-22 InfoSec Handlers Diary Blog


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ISC Stormcast For Sunday, October 22nd 2017 https://isc.sans.edu/podcastdetail.html?id=5722

Is a telco in Brazil hosting an epidemic of open SOCKS proxies?

Published: 2017-10-22
Last Updated: 2017-10-22 14:21:40 UTC
by Johannes Ullrich (Version: 1)
3 comment(s)

This is a guest diary submitted by Alan Tu. Please let us know if you like this kind of post.

I became interested in how criminals and bad actors conceal the origin point of their Internet traffic. TOR, The Onion Router project, is one common way to anonymize Internet traffic. TOR nodes allow any proxy-aware application to send traffic through the encrypted anonymity tunnel [1].

But there are other ways to route traffic other than TOR. It turns out there are lists of open proxies being posted. A person interested in anonymity, whether for good or not, can use a working and open proxy to hide the true source of Internet activity.

A tale of three sites

socks24.org ("Socks Around The Clock"), live-socks.net ("Daily Fresh Live Socks"), and vipsocks24.net ("Daily Hand-Picked Premium Servers") are three websites that appear to post a daily list of alleged open SOCKS proxies. The lists posted on September 28, 2017 are here: [2, 3, 4].

5,762 unique IP and port pairs were collected from these three lists. 5,109, or 89%, of the alleged open proxies are common to all three lists. I performed a reverse DNS lookup on all IP addresses, then sorted the results by top level domain name. Here are the top 15 domains:

 

Domain

Count

Virtua.com.br

5109

Comporium.net

42

Hinet.net

22

Cnt-grms.ec

16

Comcast.net

16

Optonline.net

14

Teletalk.net.br

12

Ip-37-59-0.eu

11

Amazonws.com

8

rr.com

8

Secureserver.net

8

Scaleway.com

8

Bahnhof.se

6

Puntonet.ec

5

Cox.net

5

 

What's going on in Brazil?

I sorted the IP addresses that resolved to virtua.com.br. The IP addresses are in 47 subnets, and according to LACNIC [5], belong to Autonomous System AS28573 assigned to Claro S.A. Claro Brazil is a large telecommunications provider.

 

Table:

Subnet, IP Addresses

177.32.0.0/14, 173

177.64.0.0/15, 1

177.80.0.0/14, 107

177.140.0.0/14, 632

177.180.0.0/14, 71

177.192.0.0/14, 54

177.0.0/16, 11

179.105.0.0/16, 18

179.152.0.0/14, 76

179.156.0.0/14, 163

179.208.0.0/14, 301

179.212.0.0/14, 10

179.216.0.0/14, 1,052

179.220.0.0/14, 13

179.232.0.0/14, 62

181.213.0.0/16, 1

181.216.0.0/13, 19

186.204.0.0/14, 230

186.220.0.0/14, 159

187.2.0.0/15, 12

187.20.0.0/14, 46

187.36.0.0/14, 151

187.64.0.0/14, 100

187.104.0.0/14, 56

187.122.0.0/15, 10

187.180.0.0/14, 27

187.255.0.0/16, 2

189.4.0.0/14, 92

189.29.0.0/16, 7

189.32.0.0/14, 141

189.54.0.0/15, 5

189.60.0.0/14, 173

189.100.0.0/14, 190

189.120.0.0/14, 489

191.176.0.0/14, 12

191.180.0.0/14, 97

191.184.0.0/14, 35

191.188.0.0/14, 28

200.160.96.0/20, 2

201.6.0.0/16, 12

201.17.0.0/16, 8

201.21.0.0/16, 3

201.37.0.0/16, 35

201.52.0.0/15, 148

201.74.0.0/16, 2

201.76.16.0/20, 2

201.80.0.0/14, 70

 

 

References:

[1] https://www.torproject.org/docs/tor-manual.html.en

[2] http://www.socks24.org/2017/09/28-09-17-vip-socks-5_18.html

[3] http://www.live-socks.net/2017/09/28-09-17-socks-5-servers-5470.html

[4] http://www.vipsocks24.net/2017/09/28-09-17-vip-socks-5-servers-5320.html

[5] https://lacnic.net/cgi-bin/lacnic/whois

 

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