Cupsd Listen arbitrary chmod 0140777

OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.8 and earlier, when starting the cupsd server with a Listen configuration item pointing to a symbolic link, the cupsd process can be caused to perform an arbitrary chmod of the provided argument, providing world-writable access to the target. Given that cupsd is often running as root, this can result in the change of permission of any user or system files to be world writable. Given the aforementioned Ubuntu AppArmor context, on such systems this vulnerability is limited to those files modifiable by the cupsd process. In that specific case it was found to be possible to turn the configuration of the Listen argument into full control over the cupsd.conf and cups-files.conf configuration files. By later setting the User and Group arguments in cups-files.conf, and printing with a printer configured by PPD with a `FoomaticRIPCommandLine` argument, arbitrary user and group (not root) command execution could be achieved, which can further be used on Ubuntu systems to achieve full root command execution. Commit ff1f8a623e090dee8a8aadf12a6a4b25efac143d contains a patch for the issue.

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

在文件访问前对链接解析不恰当(链接跟随)

OpenPrinting CUPS 安全漏洞

OpenPrinting CUPS是OpenPrinting公司的一个适用于 Linux® 和其他类 Unix® 操作系统的基于标准的开源打印系统。 OpenPrinting CUPS 2.4.8 及之前版本存在安全漏洞，该漏洞源于当使用指向符号链接的 Listen 配置项启动 cupsd 服务器时，会导致 cupsd 进程对所提供参数执行任意 chmod，从而为目标提供可全局写入的访问权限。

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