Home Cyber Security News Linux SUDO Vulnerability Found That Allows Low Privileged Users To Run Commands As Root

Linux SUDO Vulnerability Found That Allows Low Privileged Users To Run Commands As Root

by Abeerah Hashim
Linux SUDO vulnerability

Researchers have discovered a security vulnerability in the Linux SUDO command that threatens numerous Linux servers. The flaw could allow arbitrary users to run commands as root on target devices.

Linux SUDO Vulnerability Discovered

A researcher from Apple Information Security, Joe Vennix, discovered a security flaw targeting Linux servers. The vulnerability primarily existed in the Linux SUDO command, allowing low privileged users to run commands as root.

Essentially, the SUDO command (superuser do) allows underprivileged users to run root commands on a Linux device. SUDO, however, only allows this privilege when configured to do so, or when the underprivileged user knows the root password. SUDO also allows a user to run commands as another user when configured accordingly.

Due to the bug, SUDO functioned abnormally, allowing anyone to bypass the check. Thus, even when the configuration disallowed underprivileged users to run root commands, SUDO would let them bypass with UID -1 or 4294967295.

According to the description in the security advisory,

When sudo is configured to allow a user to run commands as an arbitrary user via the ALL keyword in a Runas specification, it is possible to run commands as root by specifying the user ID -1 or 4294967295.

This can be used by a user with sufficient sudo privileges to run commands as root even if the Runas specification explicitly disallows root access as long as the ALL keyword is listed first in the Runas specification.

The advisory also details the exploit for the vulnerability CVE-2019-14287.

Patch Rolled Out

Fortunately many Linux servers remain unaffected. This is because the vulnerability mainly works for non-standard configurations allowing arbitrary user IDs.

Exploiting the bug requires that the user have sudo privileges that allow them to run commands with an arbitrary user ID. Typically, this means that the user’s sudoers entry has the special value ALL in the Runas specifier.

Since this isn’t the default configuration, most Linux users remain unaffected from the flaw.

Nonetheless, for those with the vulnerable configuration, the flaw affects Sudo versions prior to 1.8.28. Thus, upgrading systems to sudo 1.8.28 is essential to stay protected from the risk of exploit.

You may also like

Do NOT follow this link or you will be banned from the site!

Privacy Preference Center

Necessary

The __cfduid cookie is used to identify individual clients behind a shared IP address and apply security settings on a per-client basis.

cookie_notice_accepted and gdpr[allowed_cookies] are used to identify the choices made from the user regarding cookie consent.

For example, if a visitor is in a coffee shop where there may be several infected machines, but the specific visitor's machine is trusted (for example, because they completed a challenge within your Challenge Passage period), the cookie allows Cloudflare to identify that client and not challenge them again. It does not correspond to any user ID in your web application, and does not store any personally identifiable information.

__cfduid, cookie_notice_accepted, gdpr[allowed_cookies]

Advertising

DoubleClick by Google refers to the DoubleClick Digital Marketing platform which is a separate division within Google. This is Google’s most advanced advertising tools set, which includes five interconnected platform components.

DoubleClick Campaign Manager: the ad-serving platform, called an Ad Server, that delivers ads to your customers and measures all online advertising, even across screens and channels.

DoubleClick Bid Manager – the programmatic bidding platform for bidding on high-quality ad inventory from more than 47 ad marketplaces including Google Display Network.

DoubleClick Ad Exchange: the world’s largest ad marketplace for purchasing display, video, mobile, Search and even Facebook inventory.

DoubleClick Search: is more powerful than AdWords and used for purchasing search ads across Google, Yahoo, and Bing.

DoubleClick Creative Solutions: for designing, delivering and measuring rich media (video) ads, interactive and expandable ads.

doubleclick

Analytics

The _ga is asssociated with Google Universal Analytics - which is a significant update to Google's more commonly used analytics service. This cookie is used to distinguish unique users by assigning a randomly generated number as a client identifier. It is included in each page request in a site and used to calculate visitor, session and campaign data for the sites analytics reports. By default it is set to expire after 2 years, although this is customisable by website owners.

The _gat global object is used to create and retrieve tracker objects, from which all other methods are invoked. Therefore the methods in this list should be run only off a tracker object created using the _gat global variable. All other methods should be called using the _gaq global object for asynchronous tracking.

_gid works as a user navigates between web pages, they can use the gtag.js tagging library to record information about the page the user has seen (for example, the page's URL) in Google Analytics. The gtag.js tagging library uses HTTP Cookies to "remember" the user's previous interactions with the web pages.

_ga, _gat, _gid