All posts by Daniel Thomas

Ethical issues in research using datasets of illicit origin

On Friday at IMC I presented our paper “Ethical issues in research using datasets of illicit origin” by Daniel R. Thomas, Sergio Pastrana, Alice Hutchings, Richard Clayton, and Alastair R. Beresford. We conducted this research after thinking about some of these issues in the context of our previous work on UDP reflection DDoS attacks.

Data of illicit origin is data obtained by illicit means such as exploiting a vulnerability or unauthorized disclosure, in our previous work this was leaked databases from booter services. We analysed existing guidance on ethics and papers that used data of illicit origin to see what issues researchers are encouraged to discuss and what issues they did discuss. We find wide variation in current practice. We encourage researchers using data of illicit origin to include an ethics section in their paper: to explain why the work was ethical so that the research community can learn from the work. At present in many cases positive benefits as well as potential harms of research, remain entirely unidentified. Few papers record explicit Research Ethics Board (REB) (aka IRB/Ethics Commitee) approval for the activity that is described and the justifications given for exemption from REB approval suggest deficiencies in the REB process. It is also important to focus on the “human participants” of research rather than the narrower “human subjects” definition as not all the humans that might be harmed by research are its direct subjects.

The paper and the slides are available.

1000 days of UDP amplification DDoS attacks

 

We presented “1000 days of UDP amplification DDoS attacks”¬†at APWG’s eCrime 2017 conference last week in Scottsdale Arizona. The paper is here, and the slides from Daniel Thomas’s talk are here.

Distributed Denial of Service (DDoS) attacks employing reflected UDP amplification are regularly used to disrupt networks and systems. The amplification allows one rented server to generate significant volumes of data, while the reflection hides the identity of the attacker. Consequently this is an attractive, low risk, strategy for criminals bent on vandalism and extortion. Despite this, many of these criminals have been arrested.

These reflected UDP amplification attacks work by spoofing the source IP address on UDP packets sent from networks that negligently fail to implement BCP38/SAVE. Since UDP (unlike TCP) does not validate the source address, the much larger responses go to the attacker’s intended victim as they spoof the victim’s address on the packets they send out. There are many protocols that can be exploited in this way including DNS and NTP.

To measure the use of this strategy we analysed the results of running a network of honeypot UDP reflectors from July 2014 onwards. We explored the life cycle of attacks that use our honeypots, from the scanning phase used to detect our honeypot machines, through to their use in attacks. We see a median of 1450 malicious scanners per day across all UDP protocols, and have recorded details of 5.18 million subsequent attacks involving in excess of 3.31 trillion packets. We investigated the length of attacks and found that most are very short, but some last for days.

To estimate the total number of attacks that occurred, including those our honeypots did not observe, we used a capture-recapture statistical technique. From this we estimated that our honeypots can see between 85.1% and 96.6% of UDP reflection attacks over our measurement period.

We observe wide variation in the number of attacks per day over the course of the measurement period as attacks using different protocols went in and out of fashion.

This work is ongoing and data from our honeypot network is available to researchers through the Cambridge Cybercrime Centre.

Also, if you want to help stop these attacks being possible you could help CAIDA by
running their spoofer prober software that checks which ISPs are negligently failing to implement BCP38/SAVE.