UPDATE : 2020.8.6 목 15:54

[Vol.81]Site Blocking with SNI Snooping : Is it a ‘Big Brother’ Policy?

정부 불법 유해사이트 차단 정책에 따른 논란 문효연 기자l승인2019.06.05l수정2019.06.05 21:10







  On February 12, 2019, the Korea Communications Commissions (KCC) strengthened the access ban to block some sites which provide illegal information such as illegal pornography and gambling service. This announcement has stirred up controversy. Blue House national petition opposing the policy was supported by 269,180 people in a month and about 300 people even gathered to protest. In response, KCC elucidated that legitimate porn or gambling would not be affected by blocking.  Nevertheless, some petitions have uploaded consistently and the controversy persists.


# What is ‘SNI Blocking Policy’?

  To better understand the blocking technology using Server Name Indication(SNI), understanding the existing internet communication and blocking method is required.

 The most commonly used way for internet access is ‘HTTP’. Using the HTTP, people could access internet sites by sending and receiving unencrypted IP addresses, so the contents of internet communication are easily revealed.The method banning access at that time was ‘DNS (Domain Name Server) Blocking policy’. It prevents users from illegal sites by connecting them to another site ‘warning.or.kr’ which has a different IP address from the requested sites. However, this way has been criticized because it is bypassed easily using a VPN(Virtual Private Network).

  In addition, several web sites such as Google and Naver started using ‘HTTPS’ rather than ‘HTTP’ as it is a more secure way of internet access. This method cannot be blocked by DNS blocking policy because all communication contents are encrypted. It means that the IP address which a user approaches cannot be figured out and be replaced with the warning site. Therefore, the government applied the way of blocking using SNI (Same Name Indication) fields. The policy includes snooping SNI fields which have unencrypted information of the hostname of the target server. This allows service providers to see which ‘HTTPS sites’ users are trying to access so these can be blocked if they are on the blacklist. If the user tries to access illegal sites, it will be connected to a black screen.


#Concerns over Internet eavesdropping and censorship

  Some point out that the government's actions are Internet eavesdropping and censorship in that communication contents are open to the government. The writer of the Blue House national petition expressed concerns saying “’HTTPS’ allowed us to present criticisms or opinions freely. However, if it is blocked, it could result in eavesdropping on those not favorable to the government.”

  Criticism about hasty enforcement is also raised because there are no institutional measures to prevent internet censorship. There is only a statement about standards of the blacklist on ‘Act on promotion of information and communications network utilization and information protection, etc.’ which is the basis of implementation.


#SNI snooping limiting freedom of using Internet

 There are also criticisms that it is an infringement of the freedom to use the Internet in the sense that some sites are totally blocked. A lawyer Lee Geun-woo said, “It is problematic to totally block the sites considered harmful in the eyes of the nation in terms of the freedom to access the internet.

  Furthermore, some people claim that the policy would prevent people from legal porn consumption. Lists of the banned sites are not revealed. Therefore, some people argued that legal porn sites can be blocked while people don’t know whether they are being blocked or not. It led to a protest with signs reading, “It is unfair to ban wearing trench coats in order to catch a flasher”.


#Elucidation of KCC about the concerns

  KCC argued that the new blocking policy was not related to eavesdropping and censorship. Under the Protection of Communications Secrets Act, eavesdropping refers to switching encrypted information into decrypted one and finding out the contents. Therefore, as the policy is conducted using information from unencrypted and exposed areas called ‘SNI fields’, it is not eavesdropping.

  KCC also refuted the argument about violating freedom. It explained that illegal sites subject to the blocking will be reviewed by KSCS in accordance with the criteria based on relevant laws and regulations, such as the Criminal Act, the Sexual Violence Punishment Act, the Information and Communication Network Act, which means there would be no arbitrary judgment.


#Advantage of SNI Blocking policy

Meanwhile, some people are favorable to the policy for the reason that it is useful in helping victims of illegal filming and sexual violence. Seo Lang, a representative of Korea Cyber Sexual Violence Response Center said, "When there was no ‘SNI blocking policy’, less than 10 percent of the sites were actually blocked, no matter how many illegal foreign sites were reported. Many victims have been saved from this policy.” In fact, a total of 6,233 illegal sites were blocked as of March 11, according to data released by KCC.


#Concerns over the effectiveness

  Criticism about the effectiveness of the method was also raised. Indeed, on the day when the policy was introduced, postings related to bypassing began to appear on the Internet. Several postings include the ways of utilizing ESNI technology to encrypt even the SNI field, using a browser with a VPN that bypasses the access path, and using the Max Transmission Unit (MTU).

  As such, various arguments have been raised about SNI snooping policy. Despite the elucidation, concerns over the internet censorship and privacy infringement still persist. Claims that the policy suppresses legitimate porn and freedom of expression are also presented. In contrast, some support the policy, saying it is helpful for coping with illegal filming and gambling. Since the policy is related to not only the use of the Internet but also to crime, how about paying attention to the policy constantly so that supplementary measures for proper use without abuse can be made?


문효연 기자  boime0824@gmail.com
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