Posts Tagged: GitHub

Apr 15

Don’t Be Fodder for China’s ‘Great Cannon’

China has been actively diverting unencrypted Web traffic destined for its top online search service — — so that some visitors from outside of the country were unwittingly enlisted in a novel and unsettling series of denial-of-service attacks aimed at sidelining sites that distribute anti-censorship tools, according to research released this week.

The findings, published in a joint paper today by researchers with University of Toronto’s Citizen Lab, the International Computer Science Institute (ICSI) and the University of California, Berkeley, track a remarkable development in China’s increasingly public display of its evolving cyber warfare prowess.

“Their willingness to be so public mystifies me,” said Nicholas Weaver, a researcher at the ICSI who helped dig through the clues about the mysterious attack. “But it does appear to be a very public statement about their capabilities.”


Earlier this month, Github — an open-source code repository — and, which distributes software to help Chinese citizens evade censorship restrictions enacted by the so-called “Great Firewall of China,” found themselves on the receiving end of a massive and constantly-changing attack apparently designed to prevent people from being able to access the sites.

Experts have long known that China’s Great Firewall is capable of blocking Web surfers from within the country from accessing online sites that host content which is deemed prohibited by the Chinese government. But according to researchers, this latest censorship innovation targeted Web surfers from outside the country who were requesting various pages associated with Baidu, such that Internet traffic from a small percentage of surfers outside the country was quietly redirected toward Github and

This attack method, which the researchers have dubbed the “Great Cannon,” works by intercepting non-Chinese traffic to Baidu Web properties, Weaver explained.

“It only intercepts traffic to a certain set of Internet addresses, and then only looks for specific script requests. About 98 percent of the time it sends the Web request straight on to Baidu, but about two percent of the time it says, ‘Okay, I’m going to drop the request going to Baidu,’ and instead it directly provides the malicious reply, replying with a bit of Javascript which causes the user’s browser to participate in a DOS attack, Weaver said. Continue reading →

Apr 14

‘Heartbleed’ Bug Exposes Passwords, Web Site Encryption Keys

Researchers have uncovered an extremely critical vulnerability in recent versions of OpenSSL, a technology that allows millions of Web sites to encrypt communications with visitors. Complicating matters further is the release of a simple exploit that can be used to steal usernames and passwords from vulnerable sites, as well as private keys that sites use to encrypt and decrypt sensitive data.




“The Heartbleed bug allows anyone on the Internet to read the memory of the systems protected by the vulnerable versions of the OpenSSL software. This compromises the secret keys used to identify the service providers and to encrypt the traffic, the names and passwords of the users and the actual content. This allows attackers to eavesdrop communications, steal data directly from the services and users and to impersonate services and users.”

An advisory from Carnegie Mellon University’s CERT notes that the vulnerability is present in sites powered by OpenSSL versions 1.0.1 through 1.0.1f. According to Netcraft, a company that monitors the technology used by various Web sites, more than a half million sites are currently vulnerable. As of this morning, that included, and — ironically — the Web site of This list at Github appears to be a relatively recent test for the presence of this vulnerability in the top 1,000 sites as indexed by Web-ranking firm Alexa.

An easy-to-use exploit that is being widely traded online allows an attacker to retrieve private memory of an application that uses the vulnerable OpenSSL “libssl” library in chunks of 64kb at a time. As CERT notes, an attacker can repeatedly leverage the vulnerability to retrieve as many 64k chunks of memory as are necessary to retrieve the intended secrets.

Jamie Blasco, director of AlienVault Labs, said this bug has “epic repercussions” because not only does it expose passwords and cryptographic keys, but in order to ensure that attackers won’t be able to use any data that does get compromised by this flaw, affected providers have to replace the private keys and certificates after patching the vulnerable OpenSSL service for each of the services that are using the OpenSSL library [full disclosure: AlienVault is an advertiser on this blog].

It is likely that a great many Internet users will be asked to change their passwords this week (I hope). Meantime, companies and organizations running vulnerable versions should upgrade to the latest iteration of OpenSSL – OpenSSL 1.0.1g — as quickly as possible.

Update, 2:26 p.m.: It appears that this Github page allows visitors to test whether a site is vulnerable to this bug (hat tip to Sandro Süffert). For more on what you can do you to protect yourself from this vulnerability, see this post.

Mar 12

Hackers Offer Bounty for Windows RDP Exploit

A Web site that bills itself as a place where independent and open source software developers can hire each other has secured promises to award at least $1,435 to the first person who can develop a working exploit that takes advantage of newly disclosed and dangerous security hole in all supported versions of Microsoft Windows.

That reward, which is sure to only increase with each passing day, is offered to any developer who can devise an exploit for one of two critical vulnerabilities that Microsoft patched on Tuesday in its Remote Desktop Protocol (RDP is designed as a way to let administrators control and configure machines remotely over a network).

Update, 8:47 a.m.: The RDP exploit may already be available. There are unconfirmed reports that a working exploit for the RDP bug has been posted to Chinese-language forums.

Original post:

The bounty comes courtesy of contributors to (pronounced gun-yo), a site that advances free and open software. The current bounty offered for the exploit is almost certainly far less than the price such a weapon could command the underground market, or even what a legitimate vulnerability research company like TippingPoint might pay for such research. But the site shows promise for organizing a grassroots effort at crafting exploits that can be used by attackers and defenders alike to test the security of desktops and the networks in which they run.

“We’re trying to advance the culture of independent software development – so we’ve made a place where indie developers can find other devs to help work on their projects and find gigs to work on when they need cash,” explains on the About section of the site. is the brainchild of Rich Jones, a 23-year-old Bostonite who just moved to Berkeley, Calif. Most recently, Jones ran a research P2P project called Anomos, which is an anonymous variant of the BitTorrent protocol. He also runs the OpenWatch Project, which uses mobile technology as a way of surveilling the police and other people in positions of power.

“I started after working for a few years as a freelance developer and open source programmer,” Jones said in an email interview. “I wanted a way to get high quality, short term freelance jobs while also continuing to contribute back to the open source community. I’m particularly interested in the things that happen when people pool their money together, so we provide a free group fundraising platform for open source projects.” quietly launched about six months ago, and has already gained thousands of contributors. Until this week it had never offered a bounty for a software exploit, Jones said. Continue reading →