LinkedIn Online Service OAuth 2.0 Covert Redirect Web Security Bugs (Information Leakage & Open Redirect)

logolinkedin

 

LinkedIn Online Service OAuth 2.0 Covert Redirect Web Security Bugs (Information Leakage & Open Redirect)

 

(1) Domain:
linkedin.com

 

“LinkedIn /ˌlɪŋkt.ˈɪn/ is a business-oriented social networking service. Founded in December 2002 and launched on May 5, 2003, it is mainly used for professional networking. In 2006, LinkedIn increased to 20 million members. As of March 2015, LinkedIn reports more than 364 million acquired users in more than 200 countries and territories. The site is available in 24 languages, including Arabic, Chinese, English, French, German, Italian, Portuguese, Spanish, Dutch, Swedish, Danish, Romanian, Russian, Turkish, Japanese, Czech, Polish, Korean, Indonesian, Malay, and Tagalog. As of 2 July 2013, Quantcast reports LinkedIn has 65.6 million monthly unique U.S. visitors and 178.4 million globally, a number that as of 29 October 2013 has increased to 184 million. In June 2011, LinkedIn had 33.9 million unique visitors, up 63 percent from a year earlier and surpassing MySpace. LinkedIn filed for an initial public offering in January 2011 and traded its first shares on May 19, 2011, under the NYSE symbol “LNKD”.” (Wikipedia)

 

 

 

 

(2) Vulnerability Description:

LinkedIn web application has a computer security problem. Hacker can exploit it by Covert Redirect cyber attacks.

 

The vulnerabilities can be attacked without user login. Tests were performed on Microsoft IE (10.0.9200.16750) of Windows 8, Mozilla Firefox (34.0) & Google Chromium 39.0.2171.65-0 ubuntu0.14.04.1.1064 (64-bit) of Ubuntu (14.04),Apple Safari 6.1.6 of Mac OS X Lion 10.7.

 

 

 


(2.1) Vulnerability Detail:

Linkedin’s OAuth 2.0 system is susceptible to Attacks. More specifically, the authentication of parameter “&redirct_uri” in OAuth 2.0 system is insufficient. It can be misused to design Open Redirect Attacks to Linkedin.

 

It increases the likelihood of successful Open Redirect Attacks to third-party websites, too.

 

LinkedIn replied with thanks and said that they “have published a blog post on how [they] intend to address [the problem].”

 

 

Blog address:
https://developer.linkedin.com/blog/register-your-oauth-2-redirect-urls

 

 

The vulnerabilities occurs at page “/oauth2/authorization?” with parameter “&redirect_uri”, e.g.
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=773svxj8m007qf&state=5316b8f3ea22a6.60933041&redirect_uri=http%3A%2F%2Fwww.inc.com%2Flogout%3Fret%3Dhttp%3A%2F%2Fwww.tetraph.com%2Fessayjeans%2Fpoems%2Fthatday.html [1]

 

When a logged-in Linkedin user clicks the URL ([1]) above, he/she will be asked for consent as in whether to allow a third-party website to receive his/her information. If the user clicks OK, he/she will be then redirected to the URL assigned to the parameter “&redirect_uri”.

 

If a user has not logged onto Linkedin and clicks the URL ([1]) above, the same situation will happen upon login.

 

 

 

(2.1.1) Linkedin would normally allow all the URLs that belong to the domain of an authorized third-party website. However, these URLs could be prone to manipulation. For example, the “&redirect_uri” parameter in the URLs is supposed to be set by the third-party websites, but an attacker could change its value to make Attacks.

 

Hence, a user could be redirected from Linkedin to a vulnerable URL in that domain first and later be redirected from this vulnerable site to a malicious site unwillingly. This is as if the user is redirected from Linkedin directly. The number of Linkedin’s OAuth 2.0 client websites is so huge that such Attacks could be commonplace.

 

Linkedin’s OAuth 2.0 system makes the redirects appear more trustworthy and could potentially increase the likelihood of successful Open Redirect Attacks of third-party website.

 

At the same time, attackers could completely bypass Linkedin’s authentication system and attack more easily.

 

It might be of Linkedin’s interest to patch up against such attacks.

 

 

 

(2.2) Use one of webpages for the following tests. The webpage is “http://homehut.lofter.com/“. Can suppose it is malicious.

 

Below is an example of a vulnerable third-party domain:
inc.com

 

Vulnerable URL in this domain:
http://www.inc.com/logout?ret=http://www.tetraph.com/essayjeans/poems/thatday.html

 

Vulnerable URL from Linkedin that is related to inc.com:
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=773svxj8m007qf&state=53169feb993957.93834988&redirect_uri=http%3A%2F%2Fdev-www.inc.com%2Fpatch%2Freflex%2Flib%2Flinkedin%2Fstartlogin.php

 

POC:
https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=773svxj8m007qf&state=5316b8f3ea22a6.60933041&redirect_uri=http%3A%2F%2Fwww.inc.com%2Flogout%3Fret%3Dhttp%3A%2F%2Fwww.tetraph.com%2Fessayjeans%2Fpoems%2Fthatday.html

 

 


POC Video:
https://www.youtube.com/watch?v=iif6eq2cvso

 

Blog Detail:
http://tetraph.blogspot.com/2014/05/linkedin-oauth-20-covert-redirect.html

 

 

 

(3) What is Covert Redirect?

Covert Redirect is a class of security bugs disclosed in May 2014. It is an application that takes a parameter and redirects a user to the parameter value without sufficient validation. This often makes use of Open Redirect and XSS (Cross-site Scripting) vulnerabilities in third-party applications.

 

Covert Redirect is also related to single sign-on. It is known by its influence on OAuth and OpenID. Hacker may use it to steal users’ sensitive information. Almost all OAuth 2.0 and OpenID providers worldwide are affected. Covert Redirect can work together with CSRF (Cross-site Request Forgery) as well.



 

Discover and Reporter:
Wang Jing, Division of Mathematical Sciences (MAS), School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University (NTU), Singapore. (@justqdjing)
http://tetraph.com/wangjing/

 

 

 

 

 

Related Articles:
http://tetraph.com/security/covert-redirect/linkedin-oauth-2-0-covert-redirect-vulnerability/
http://computerobsess.blogspot.com/2014/07/linkedin-service-exploit.html
https://twitter.com/tetraphibious/status/559169110106316800
https://webtechwire.wordpress.com/2014/06/07/linkedin-bugs/
http://securityrelated.blogspot.com/2014/07/linkedin-service-exploit.html
http://ithut.tumblr.com/post/119493922098/securitypost-itinfotech-continuan-los
http://tetraph.blog.163.com/blog/static/23460305120144385617661/
https://computertechhut.wordpress.com/2014/06/11/linkedin-bugs/
http://itsecurity.lofter.com/post/1cfbf9e7_70608ba
http://www.inzeed.com/kaleidoscope/covert-redirect/linkedin-oauth-2-0-covert-redirect-vulnerability/

 

Facebook, Google Users Threatened by New Security Flaw, Covert Redirect

images18

 

A serious flaw in two widely used security standards could give anyone access to your account information at Google, Microsoft, Facebook, Twitter and many other online services. The flaw, dubbed “Covert Redirect” by its discoverer, exists in two open-source session-authorization protocols, OAuth 2.0 and OpenID.

 

Both standards are employed across the Internet to let users log into websites using their credentials from other sites, such as by logging into a Web forum using a Facebook or Twitter username and password instead of creating a new account just for that forum.

 

Attackers could exploit the flaw to disguise and launch phishing attempts from legitimate websites, said the flaw’s finder, Mathematics Ph.D. student Wang Jing of the Nanyang Technological University in Singapore.

 

Wang believes it’s unlikely that this flaw will be patched any time soon. He says neither the authentication companies (those with which users have an account, such as Google, Microsoft, Facebook, Twitter or LinkedIn, among others) nor the client companies (sites or apps whose users log in via an account from an authentication company) are taking responsibility for fixing the issue.

 

“The vulnerability is usually due to the existing weakness in the third-party websites,” Wang writes on his own blog. “However, they have little incentive to fix the problem.”

 

The biggest danger of Covert Redirect is that it could be used to conduct phishing attacks, in which cybercriminals seize login credentials, by using email messages containing links to malicious websites disguised as something their targets might want to visit.

 

Normal phishing attempts can be easy to spot, because the malicious page’s URL will usually be off by a couple of letters from that of the real site. The difference with Covert Redirect is that an attacker could use the real website instead by corrupting the site with a malicious login popup dialogue box.

 

For example, say you regularly visit a given forum (the client company), to which you log in using your credentials from Facebook (the authentication company). Facebook uses OAuth 2.0 to authenticate logins, so an attacker could put a corrupted Facebook login popup box on this forum.

 

If you sign in using that popup box, your Facebook data will be released to the attacker, not to the forum. This means the attacker could possibly gain access to your Facebook account, which he or she could use to spread more socially engineered attacks to your Facebook friends.

 

Covert Redirect could also be used in redirection attacks, which is when a link takes you to a different page than the one expected.

 

Wang told CNET authentication companies should create whitelists — pre-approved lists that block any not on it — of the client companies that are allowed to use OAuth and OpenID to redirect to them. But he said he had contacted a number of these authentication companies, who all shifted blame elsewhere.

 

Wang told CNET Facebook had told him it “understood the risks associated with OAuth 2.0” but that fixing the flaw would be “something that can’t be accomplished in the short term.” Google and LinkedIn allegedly told Wang they were looking into the issue, while Microsoft said the issue did not exist on its own sites.

 

Covert Redirect appears to exist in the implementations of the OpenID and OAuth standards used on client websites and apps. But because these two standards are open-source and were developed by a group of volunteers, there’s no company or dedicated team that could devote itself to fixing the issue.

 

 

Where does that leave things?

“Given the trust users put in Facebook and other major OAuth providers, I think it will be easy for attackers to trick people into giving some access to their personal information stored on those service,” Chris Wysopal, chief technology officer of Boston-area security firm Veracode and a member of the legendary 1990s hackerspace the L0pht, told CNET.

 

“It’s not easy to fix, and any effective remedies would negatively impact the user experience,” Jeremiah Grossman, founder of Santa Clara, Calif.-based WhiteHat Security, told CNET. “Just another example that Web security is fundamentally broken and the powers that be have little incentive to address the inherent flaws.”

 

Users should be extra-wary of login popups on Web pages. If you wish to log into a given website, it might be better to use an account specific to that website instead of logging in with Facebook, Twitter, or another authentication company, which would require the use of OAuth and/or OpenID to do.

 

If you think someone has gained access to one of your online accounts, notify the service and change that account’s password immediately.

 

 

 

 

 

Related Articles:

http://www.tomsguide.com/us/facebook-google-covert-redirect-flaw,news-18726.html

http://www.scmagazine.com/covert-redirect-vulnerability-impacts-oauth-20-openid/article/345407/

http://news.yahoo.com/facebook-google-users-threatened-security-192547549.html

http://thehackernews.com/2014/05/nasty-covert-redirect-vulnerability.html

http://www.foxnews.com/tech/2014/05/05/facebook-google-users-threatened-by-new-security-flaw/

http://whitehatview.tumblr.com/post/120695795041

http://russiapost.blogspot.ru/2015/05/openid-oauth-20.html

http://www.diebiyi.com/articles/security/covert-redirect/covert_redirect/

https://itswift.wordpress.com/2014/05/06/microsoft-google-facebook-attacked/

http://tetraph.blog.163.com/blog/static/2346030512015420103814617/

http://itsecurity.lofter.com/post/1cfbf9e7_72e2dbe

http://ithut.tumblr.com/post/119493304233/securitypost-une-faille-dans-lintegration

http://japanbroad.blogspot.jp/2015/05/oauthopenid-facebook.html

http://webtech.lofter.com/post/1cd3e0d3_6f0f291

https://webtechwire.wordpress.com/2014/05/11/covert-redirect-attack-worldwide/

http://whitehatview.tumblr.com/post/119489968576/securitypost-sicherheitslucke-in-oauth-2-0-und

http://www.inzeed.com/kaleidoscope/computer-security/facebook-google-attack/