顽固漏洞再现Linux内核

顽固漏洞再现Linux内核

“从这里获得你的根权限”

The Linux kernel has been purged of a bug that gave root access to untrusted users – again.

又一次，Linux内核清除了一个提供给不受信任者根权限的漏洞。

The vulnerability in a component of the operating system that translates values from 64 bits to 32 bits (and vice versa) was fixed once before – in 2007 with the release of version 2.6.22.7. But several months later, developers inadvertently rolled back the change, once again leaving the OS open to attacks that allow unprivileged users to gain full root access.

操作系统某一组件中从64位向32（反之亦可）传值时所引发的风险曾被修复过——于2007年的2.6.22.7版中。可是几个月后，开发者无意地回滚了所作修复，又一次让操作系统置身于有被非特权用户夺取完全根权限之可能的高危风险中。

The bug was originally discovered by the late hacker Wojciech "cliph" Purczynski. But Ben Hawkes, the researcher who discovered the kernel regression bug, said here that he grew suspicious when he recently began tinkering under the hood of the open-source OS and saw signs the flaw was still active.

漏洞最初是由已故的黑客Wojciech "cliph" Purczynski发现的。但是Ben Hawkes，发现内核回滚漏洞的调查者，此时说，在最近对操作系统作修补的过程中，他越来越心生疑虑了。

“I showed this to my friend Robert Swiecki who had written an exploit for the original bug in 2007, and he immediately said something along the lines of 'well this is interesting,'” Hawkes wrote. “We pulled up his old exploit from 2007, and with a few minor modifications to the privilege escalation code, we had a root shell.”

“我把它展示给2007年曾为修复原先这一漏洞作出了大量开发工作的朋友Robert Swiecki看。‘啊，这真奇怪！’他说。”Hawkes写道。“我们从2007年开发存档中取出了修复方法，对特权增强代码作了一些小的更改，写成了一个root shell。”

No doubt, Linux fans will be quick to point out that the bug can be exploited only by those with a valid account on a targeted machine in the first place. This is true, but the existence of vulnerabilities like these are a big deal in corporate, government and educational environments, where Linux is a mainstay has a large following. Add privilege escalation to the mix and things like protected mode, integrity levels, and chroot – often the very reason the OS was chosen in the first place – are largely wiped out.

无疑，Linux热衷者会很快指出，那一漏洞只会被在目标机器上已有合法帐户的人利用。这是事实，可是这种风险在公司、政府和教育机构等Linux成了中流砥柱有巨大用武之地的领域里存在便是大事情。并且权限增强以及保护模式、级别集成、chroot——这些功能大多是此款操作系统被首选的原因——功能会被大大削弱。

The oversight means that untrusted users with, say, limited SSH access have a trivial means to gain unfettered access to pretty much any 64-bit installation. Consider, too, that the bug has been allowed to fester in the kernel for years and was already fixed once before and we think a measured WTF is in order.

这一漏洞意味着持比如有限SSH访问权限的不受信任用户有一种小方法能获取不受限的访问诸多64位安装的权限。

It was one of two privilege-elevation vulnerabilities Hawkes disclosed on Wednesday in the Linux 32-bit compatibility mode. The official updates are here, here and here. ®

这是Hawkes周三在Linux 32位兼容模式下发现的两大权限增强风险漏洞之一。官方更新在这，这还有这。