WFCrawler: a toolkit for crawling top ranking sites

This is the repository of WFCrawler. Similar as Tor Browser Crawler, it crawls top sites and parses them into traces for Website Fingerprinting (WF) research. It is customized for WFDefProxy, a pluggable transport which implements a bunch of WF defenses.

Only for research purposed, please use carefully!

How to use?

We use tbselenium to launch the tor browser. We use stem to control Tor. To launch a crawl, use the cmd: python crawler.py [args]. There are some key arguments:

• -w: to provide a path to the website list. If not specified, it will use the default path defined in common.py: unmon_list and mon_list.
• --start: to specify the start index of the website in the list
• --end: to specify the end index of the website in the list
• --batch, -b: the number of batches crawled. After crawling a batch, Tor will be restared. (Only useful when crawling monitored websites)
• -m: the number of instances per site in each batch.
• --open: whether crawl the monitored sites or non-monitored sites.
• --mode: "clean" or "burst". Just for marking whether or not this is a defended dataset. Used for folder name initialization,
• --tbblog: provide a path to save the logs of the browser.
• --torrc: provide the path of a torrc file

To help understand the parameters, we give two examples here:

When we want to crawl a monitored dataset:

python crawler.py --start 0 --end 10 -m 3 -b 2 --open 0 --mode clean --tbblog /Users/example/crawl.log --torrc /Users/example/mytorrc

This command will crawl the websites indexed from 0 to 9 in the mon_list in a round-robin fashion: 0, 0, 0, ..., 9,9,9 (the first batch);(Tor will be restarted); 0,0,0,..., 9,9,9 (the second batch). Since m=3 and b=2, each website will be loaded 6 times in total. The crawled traces will be saved as 0-0.cell, ..., 0-5.cell, ..., 9-0.cell, ..., 9-5.cell. The dataset is saved as clean_[timestamp].

When we want to crawl a non-monitored dataset:

python crawler.py --start 200 --end 300 -m 50 --open 1 --mode clean -u --tbblog /Users/example/crawl.log --torrc /Users/example/mytorrc

This command will crawl the websites indexed from 200 to 299 in the unmon_list, each loaded once. Tor will be restarted every m=50 websites. The dataset is saved as uclean_[timestamp]. The crawled traces will be saved as 0.cell, ..., 99.cell. Note that we have a --offset parameter in the function and the default value is 200. Therefore, when visiting the 200th website, the file name is 0.cell (200 - offset).

How does it work?

The crawler uses gRPC to communicate with WFDefProxy. To start logging before a visit:

err = self.gRPCClient.sendRequest(turn_on=True, file_path='{}.cell'.format(filename)) (Line 180)

To end the logging after a visit:

self.gRPCClient.sendRequest(turn_on=False, file_path='') (Line 212)

Therefore, a raw trace will be saved as [filename].cell.

Parse the collected traces

To parse the collected traces into Wang's format, use parseTLS.py. Here is an example:

python parseTLS.py [path_to_dataset] -mode clean

The parameter definitions are similar as crawler.py. Please go and check it.

Work with Tor Browser directly

The master branch works with Selenium + Tor. We also developed another branch dev-tbb which directly launches Tor Browser with command lines. You should have a customized Tor Browser where you replace the default torrc file with yours and hopefully a tampermonkey script to automatically close Tor Browser after each visit.

Similar as before, the crawling process will be in a round-robin fashion. But we will not use gRPC anymore. Instead, each time we copy the log file of the pluggable transport (i.e., WFDefProxy) /somewhere/pt_state/obfs4proxy.log to the result folder.

To parse the raw traces, remember to use parse_log.py this time. The usage is similar as parseTLS.py though.

Tips and Tricks

You can modify some constants in common.py, such as

gRPCAddr = "localhost:10086"
BROWSER_LAUNCH_TIMEOUT = 10
SOFT_VISIT_TIMEOUT = 80
HARD_VISIT_TIMEOUT = SOFT_VISIT_TIMEOUT + 10
GAP_BETWEEN_BATCHES = 5
CRAWLER_DWELL_TIME = 3
GAP_BETWEEN_SITES_MAX = 2
GAP_AFTER_LAUNCH = 5

Versioning

The codes are tested in Python 3.7.

Acknowledgments

Some of the codes are based on the following works. We thank respective authors for being kind to share their code:

[1] M. Juarez, S. Afroz, G. Acar, C. Diaz, R. Greenstadt, Tor-Browser-Crawler

[2] Nate Mathews, Tor-Browser-Crawler