Alert 的开发者可能已经将 Linux 用户从痛苦的世界中拯救出来

一名警报开发人员似乎阻止了后门（可能由国家支持的参与者插入游说工具中）被分发到生产 Linux 系统。 恶意代码似乎允许在 SSH 身份验证期间绕过检查。

发现 xz Utils 后门的微软软件工程师 Anders Freund 表示，该恶意代码是在 5.6.0 和 5.6.1 版本中引入的。 人们怀疑这可能是国家支持的行为，因为该法律已经实施了很长时间。

弗罗因德 图书 周五：“在过去几周注意到 Debian sid 安装上的 liblzma（xz 软件包的一部分）的一些奇怪症状（使用 ssh 登录消耗大量 cpu、valgrind 错误）后，我想出了答案：上游 xz 存储库已将 xz 焦油球放置在后门中。

“起初，我认为这是对 Debian 软件包的妥协，但事实证明这是第一步。”

其中一位名为 JiaT75 的开发人员已经担任该软件包的维护者两年多了。 弗罗因德补充道：“鉴于活动已经持续了数周，肇事者要么直接参与其中，要么他们的系统受到了一些极端的损害。”

“不幸的是，鉴于他们在各种清单中谈论了上述‘改革’，后者似乎是最不可能的解释。” 他提到了可疑版主建议的各种插件来修复代码问题： 这里, 这里, 这里， 和 这里。 [Thanks to Dan Goodin for these four links.}

SSH or secure shell is an utility used to log in securely to systems, with the majority of Linux systems using a port known as OpenSSH that is maintained by the OpenBSD project, an Unix clone.

The only production Linux system in which the doctored code was distributed appears to have been the Tumbleweed stream put out by the OpenSUSE project. The developers at that project wrote on Friday: “For our openSUSE Tumbleweed users where SSH is exposed to the Internet, we recommend installing fresh, as it’s unknown if the backdoor has been exploited.

“Due to the sophisticated nature of the backdoor an on-system detection of a breach is likely not possible. Also rotation of any credentials that could have been fetched from the system is highly recommended.

“It has been established that the malicious file introduced into Tumbleweed is not present in SUSE Linux Enterprise and/or Leap. Current research indicates that the backdoor is active in the SSH Daemon, allowing malicious actors to access systems where SSH is exposed to the Internet.”

Debian issued patched versions of xz Utils for its testing, experimental and unstable streams of development. Red Hat said on Friday, “Fedora Linux 40 users may have received version 5.6.0, depending on the timing of system updates. Fedora Rawhide users may have received version 5.6.0 or 5.6.1.”

“At this time the Fedora Linux 40 builds have not been shown to be compromised. We believe the malicious code injection did not take effect in these builds. However, Fedora Linux 40 users should still downgrade to a 5.4 build to be safe.”

Later, Red Hat added: “We have determined that Fedora Linux 40 beta does contain two affected versions of xz libraries – xz-libs-5.6.0-1.fc40.x86_64.rpm and xz-libs-5.6.0-2.fc40.x86_64.rpm. At this time, Fedora 40 Linux does not appear to be affected by the actual malware exploit, but we encourage all Fedora 40 Linux beta users to revert to 5.4.x versions.”

It is likely to be quite some time before calm returns; former senior Debian developer Joey Hess provided one reason, noting that the accounts used by the suspected malicious actors had made more than 700 commits [code contributions] 近两年来。

“我算了一下，Jia Tan 对 xz 进行了至少 750 次提交或贡献，他是后门的。这包括 2023 年 1 月 7 日合并拉取请求后所做的所有 700 次提交，此时他们似乎已经拥有了付费访问权限，这还允许他们支付与假作者的承诺，并且可能在此之前还支付一些其他承诺。

“将后门恢复到以前的版本并不足以知道 Jia Tan 没有在其中隐藏其他后门。5.4.5 版本仍然包含大部分这些提交。”

他补充道：“该软件包必须恢复到之前的版本 [the bad actors’] 共享，以提交 6468f7e41a8e9c611e4ba8d34e2175c5dacdbeb4 开始。 或者他们早期的承诺 [should be] 这些内容会在稍后进行检查并返回，但是由已知的不良和恶意行为者进行的任何任意委托的价值肯定低于未注意到确切更改的风险。

“我建议恢复到 5.3.1 版本 – 请记住，在那之后有安全修复……需要重新应用。”

看来受到怀疑的人也在提供名单之外的帮助，这可能是为了讨好其他开发商，从而在出现这些提议时消除对这些提议的任何怀疑。

不出所料，这个问题已经进行了长时间的讨论； Linux 每周新闻 他有一根很长的绳子 这里， 尽管 海盗新闻 它有超过 2,000 个帖子 [when I last looked] 这里。