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Security Leftovers

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  • CVE-2021-4034 – Ariadne's Space

    Before we get into this, I have seen a lot of people on Twitter blaming systemd for this vulnerability. It should be clarified that systemd has basically nothing to do with polkit, and has nothing at all to do with this vulnerability, systemd and polkit are separate projects largely maintained by different people.

    We should try to be empathetic toward software maintainers, including those from systemd and polkit, so writing inflammatory posts blaming systemd or its maintainers for polkit does not really help to fix the problems that made this a useful security vulnerability.

  • Windows ransomware LockBit makes the jump to Linux [Ed: Pro-Windows site. Misses the point that over 90% of ransomware is a Windows problem.]

    First, they came for Windows. Then, for Tux. As cool as Linux is, it's increasingly becoming a target for ransomware-friendly cyber criminals intent on ruining people's days.

  • These critical security bugs put Linux servers at risk of attack [Ed: Attack from the inside maybe; you need to actually have an account on such machines to begin with... compare to Windows with remotely-exploitable full compromise bugs/back doors]
  • Patch Now: A newly discovered critical Linux vulnerability probably affects your systems
  • IoT security certification group gains steam [Ed: Another fake security consortium? Their shoddy products might be best off avoided altogether, as there's rarely a practical need for such gimmicks.]

    The ioXT Alliance, which offers a certification program for IoT security, announced it has certified 195 products and grown to 580 members. Meanwhile, Timesys is seeking participants for a survey on IoT security.

DARKReading

Original

  • PwnKit: Local Privilege Escalation Vulnerability Discovered in polkit’s pkexec (CVE-2021-4034)

    Polkit (formerly PolicyKit) is a component for controlling system-wide privileges in Unix-like operating systems. It provides an organized way for non-privileged processes to communicate with privileged processes. It is also possible to use polkit to execute commands with elevated privileges using the command pkexec followed by the command intended to be executed (with root permission).

This Week In Security

  • This Week In Security: Geopolitical Hacktivism, Antivirus Mining, And Linux Malware | Hackaday

    So what’s the story with pkexec? NULL argv. OK, Linux programming 101 time. When a program is launched on Linux, it’s passed two parameters, normally named argc and argv. These are an integer, and an array of char pointers respectively. If you’re not a programmer, then think of this as the number of arguments, and the list of arguments. This information is used to parse and handle command line options inside the program. argc is always at least one, and argv[0] will always contain the name of the binary as executed. Except, that isn’t always the case. There’s another way to launch binaries, using the execve() function. That function allows the programmer to specify the list of arguments directly, including argument 0.

    So what happens if that list is just NULL? If a program was written to account for this possibility, like sudo, then all is well. pkexec, however, doesn’t include a check for an empty argv or an argc of 0. It acts as if there is an argument to read, and the way the program initialization happens in memory, it actually accesses the first environment variable instead, and treats it like an argument. It checks the system PATH for a matching binary, and rewrites what it thinks is it’s argument list, but is actually the environment variable. This means that uncontrolled text can be injected as an environment variable in pkexec, the setuid program.

A couple more on polkit

  • PwnKit: detect privilege escalation with CrowdSec - The open-source & collaborative IPS

    Qualys just published CVE-2021-4034 which is trivial to exploit and impacts a large variety of distributions and versions. In a nutshell, the vulnerability, also called PwnKit, allows for a local escalation of privilege (LPE), due to out-of-band writing, in Polkit’s Pkexec, an alternate solution to the “sudo” privilege management tool. Pkexec is installed by default on most popular Linux distributions. A successful exploit can lead to handing admin/root privileges to unauthorized users.

    While everybody loves a fine LPE, it’s mostly an excuse for us to take a look at another aspect of CrowdSec: pure alerting capabilities along with remediation.

  • What Is the PwnKit Vulnerability Affecting Linux Distributions?

    Linux systems are known for being solid when it comes to security. Since most Linux programs come from trusted sources and are usually reviewed by the community, it's pretty unusual to encounter very high-impact bugs. However, this doesn't mean Linux is free from such problems altogether. The recent discovery of the PwnKit system service bug is one such example.

    The PwnKit vulnerability is a serious bug that gives root privileges to any local user. This bug is especially dangerous because it affects almost all major Linux distributions.

BankInfoSecurity

Qualys

Linux distros haunted by Polkit-geist for 12+ years

  • Linux distros haunted by Polkit-geist for 12+ years: Bug grants root access to any user

    Linux vendors on Tuesday issued patches for a memory corruption vulnerability in a component called polkit that allows an unprivileged logged-in user to gain full root access on a system in its default configuration.

    Security vendor Qualys found the flaw and published details in a coordinated disclosure.

    Polkit, previously known as PolicyKit, is a tool for setting up policies governing how unprivileged processes interact with privileged ones. The vulnerability resides within polkit's pkexec, a SUID-root program that's installed by default on all major Linux distributions. Designated CVE-2021-4034, the vulnerability has been given a CVSS score of 7.8.

    Bharat Jogi, director of vulnerability and threat research at Qualys, explained in a blog post that the pkexec flaw opens the door to root privileges for an attacker. Qualys researchers, he said, have demonstrated exploitation on default installations of Ubuntu, Debian, Fedora, and CentOS, and other Linux distributions are presumed to be vulnerable as well.

  • 12-year-old Linux root privilege flaw has been "hiding in plain sight"

    An 'easily exploitable' root privilege security vulnerability has been discovered in popular default Linux distributions and "has been hiding in plain sight" for more than 12 years, according to security researchers.

Pwnkit is an easy-to-exploit vulnerability affecting all Linux

  • Pwnkit is an easy-to-exploit vulnerability affecting all Linux distros

    Linux has been known for being way more secure than Windows PCs. However, this may be changing soon as the platform is growing in popularity. According to a new report from Cybersecurity researchers from Qualys (via TechRadar), there is an “extremely severe” vulnerability in Linux. It’s very easy to exploit bugs and is affecting every major distro for the open-source Operating System.

    According to the researchers, this vulnerability has been “hiding in plain sight” for more than 12 years, and it’s memory corruption in polkit’s pkexec. According to the researchers, it’s a SUID-root program, installed by default. The malicious actors can exploit the bug to gain full root privileges on the target machine, and then do as they please. They can use the exploit to install malware or even ransomware.

Linux Vulnerability Discovered Impacting All Major Distros

  • Linux Vulnerability Discovered Impacting All Major Distros

    A major Linux vulnerability, impacting virtual all major distributions (distros), has been discovered, allowing a bad actor to obtain root privileges.

    On Linux, Unix, macOS, and other Unix-style operating systems, the root account has ultimate access to the system. As a result, when a user account is set up, it doesn’t have root access as a way of protecting the system from accidental damage.

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