Github, an online forum¹ for software developers that also hosts tools used by Chinese internet users to bypass censorship, has been hit by a powerful cyber attack that security experts believe originated in China.

软件开发人员在线论坛网站Github遭遇强劲网络攻击，安全专家相信这次网络攻击源自中国。目前，Github网站上托管着中国互联网用户可用来绕开中国国内审查机制的工具软件。

The San Francisco-based start-up said it was experiencing the largest denial-of-service attack in its history, as cyber criminals bombarded the site with traffic in an attempt to take it offline.

这家总部驻旧金山的初创公司表示，该网站正经历建站以来最大规模的“拒绝服务”(DoS)攻击。所谓拒绝服务攻击，是指网络罪犯通过巨大的流量轰炸某个特定网站，以使其下线的网络攻击方法。

In a blog post, the company said the attack had started on Thursday and involved a “wide combination of attack vectors”, including “sophisticated new techniques that use the web browsers² of unsuspecting, uninvolved people to flood github.com with high levels of traffic”.

该公司在一篇博客文章中表示，这次网络攻击始于周四，“参与的攻击媒介涵盖范围极广”，使用了“十分复杂的新技术，通过受信任的无辜人群的网络浏览器，以极高流量水平冲击了github.com网站”。

The company said that based on reports it had received, “we believe the intent of this attack is to convince us to remove a specific class of content”.

该公司表示，根据它已收到的相关报告，“我们相信此次攻击的意图是说服我们移除特定类别的内容”。

The privately³ owned company would not specify⁴ what content was being targeted. The site is mainly used by software engineers and start-ups to store and collaborate⁵ on their work.

这家私人控股的公司不会透露具体要求移除的内容是什么。目前，使用该网站的主要是软件工程师和初创企业，他们用它存储其工作内容并开展相互合作。

But it also contains copies of some websites banned in China, including a page run by Greatfire.org that helps Chinese internet users circumvent⁶ government censorship.

不过，该网站还托管着部分中国被封网站的拷贝，其中包括Greatfire.org网站运营的一个网页。Greatfire.org是一家帮助中国互联网用户绕开政府审查机制的网站。

Security experts said the attack appeared to have originated in China, with the web browsers of foreign visitors to Baidu.com, the Chinese search engine, stealthily redirected to Github, overwhelming the site with traffic.

多名安全专家表示，此次攻击似乎源自中国，中国搜索引擎百度网站(Baidu.com)的外国访问者的浏览器被隐秘地重定向至Github网站，从而令该网站的流量超过其承受能力。

Github was temporarily blocked in China in 2013.

2013年，Github网站在中国曾被临时封禁。

Adam Fisk of Getlantern.org, a site that provides tools for bypassing China’s “Great Firewall” and hosts its installers on Github, said this kind of DDOS attack could cost a company hundreds of thousands of dollars a day, and might be aimed at putting pressure on Github to take down content that could not be blocked wholesale⁷ because Github is widely used by China’s technology industry.

Getlantern.org网站的亚当•菲斯克(Adam Fisk)表示，这种分布式拒绝服务攻击(DDoS)一天就会令企业蒙受数十万美元损失。采取这种攻击方式可能旨在向Github施加压力，迫使该网站取下无法被封禁的内容。由于中国高科技产业也在广泛使用Github网站，从整体上将该网站封禁并不可行。

“Github is hugely important to the whole internet, it’s where everyone keeps their code,” Mr Fisk said. “The more disturbing strategy shift this represents is that the Chinese are going after sites such as Github not through blocking but through denial of service attacks. It seems like what they are doing is trying to bend Github to their will, to intimidate⁸ them.”

菲斯克表示：“Github对整个互联网都至关重要，所有人都把代码放在该网站上。这次攻击显示出，中国人正通过拒绝服务实施攻击而不是封禁对付这类网站，从而将其策略转向更偏重扰乱对方运作的方式。他们的目的看起来似乎是试图恐吓Github网站，以便让该网站按照他们的意志行事。”

Github has managed to keep much of the site live during the attack. It has published regular status updates showing the attention of the hackers⁹ switching between different parts of the forum and the highest levels of traffic flooding the system in waves.

在此次攻击期间，Github成功地保持了网站大部分内容的运作。该网站发布了一份例行状态更新，显示出黑客的注意力在网站不同部分间不断转移，冲击其系统的最高流量水平也时高时低。

The US has accused the Chinese People’s Liberation Army of hacking¹⁰ into American websites, with the FBI recently investigating an attack on Register.com, which manages website addresses, according to people familiar with the probe. The Chinese military denies the accusation¹¹ and insists it is a victim in the recent global surge in cyber warfare¹².

美国曾指控中国人民解放军(PLA)攻击美国网站。知情人士表示，美国联邦调查局(FBI)最近曾对管理网址的Register.com网站遭遇的网络攻击开展过调查。中国军方否认了这一指控，坚称他们是近期全球网络战激增的受害者。