Linux kernel | Breaking Cybersecurity News | The Hacker News

Cybersecurity researchers have shed light on a novel Linux kernel exploitation technique dubbed SLUBStick that could be exploited to elevate a limited heap vulnerability to an arbitrary memory read-and-write primitive. "Initially, it exploits a timing side-channel of the allocator to perform a cross-cache attack reliably," a group of academics from the Graz University of Technology said [PDF]. "Concretely, exploiting the side-channel leakage pushes the success rate to above 99% for frequently used generic caches." Memory safety vulnerabilities impacting the Linux kernel have limited capabilities and are a lot more challenging to exploit owing to security features like Supervisor Mode Access Prevention ( SMAP ), Kernel address space layout randomization ( KASLR ), and kernel control flow integrity ( kCFI ). While software cross-cache attacks have been devised as a way to counter kernel hardening strategies like coarse-grained heap separation, studies have show...

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) on Thursday added a security flaw impacting the Linux kernel to the Known Exploited Vulnerabilities ( KEV ) catalog, citing evidence of active exploitation. Tracked as CVE-2024-1086 (CVSS score: 7.8), the high-severity issue relates to a use-after-free bug in the netfilter component that permits a local attacker to elevate privileges from a regular user to root and possibly execute arbitrary code. "Linux kernel contains a use-after-free vulnerability in the netfilter: nf_tables component that allows an attacker to achieve local privilege escalation," CISA said. Netfilter is a framework provided by the Linux kernel that allows the implementation of various network-related operations in the form of custom handlers to facilitate packet filtering, network address translation, and port translation. The vulnerability was addressed in January 2024. That said, the exact nature of the attacks exploiting the fla...

Vulnerability Management (VM) has long been a cornerstone of organizational cybersecurity. Nearly as old as the discipline of cybersecurity itself, it aims to help organizations identify and address potential security issues before they become serious problems. Yet, in recent years, the limitations of this approach have become increasingly evident.  At its core, Vulnerability Management processes remain essential for identifying and addressing weaknesses. But as time marches on and attack avenues evolve, this approach is beginning to show its age. In a recent report, How to Grow Vulnerability Management into Exposure Management (Gartner, How to Grow Vulnerability Management Into Exposure Management, 8 November 2024, Mitchell Schneider Et Al.), we believe Gartner® addresses this point precisely and demonstrates how organizations can – and must – shift from a vulnerability-centric strategy to a broader Exposure Management (EM) framework. We feel it's more than a worthwhile read an...

Cybersecurity researchers have disclosed what they say is the "first native Spectre v2 exploit" against the Linux kernel on Intel systems that could be exploited to read sensitive data from the memory. The exploit, called Native Branch History Injection (BHI), can be used to leak arbitrary kernel memory at 3.5 kB/sec by bypassing existing Spectre v2/BHI mitigations, researchers from Systems and Network Security Group (VUSec) at Vrije Universiteit Amsterdam  said  in a new study. The shortcoming is being tracked as  CVE-2024-2201 . BHI was  first disclosed  by VUSec in March 2022, describing it as a technique that can get around Spectre v2 protections in modern processors from Intel, AMD, and Arm. While the attack leveraged extended Berkeley Packet Filters (eBPFs), Intel's recommendations to address the problem, among other things, were to disable Linux's unprivileged eBPFs. "Privileged managed runtimes that can be configured to allow an unprivileged user ...

Malicious local attackers can obtain full root access on Linux machines by taking advantage of a newly disclosed security flaw in the GNU C library (aka glibc). Tracked as CVE-2023-6246 (CVSS score: 7.8), the heap-based buffer overflow vulnerability is rooted in glibc's __vsyslog_internal() function, which is used by  syslog() and vsyslog()  for system logging purposes. It's said to have been accidentally introduced in August 2022 with the release of glibc 2.37. "This flaw allows local privilege escalation, enabling an unprivileged user to gain full root access," Saeed Abbasi, product manager of the Threat Research Unit at Qualys,  said , adding it impacts major Linux distributions like Debian, Ubuntu, and Fedora. A threat actor could exploit the flaw to obtain elevated permissions via specially crafted inputs to applications that employ these logging functions. "Although the  vulnerability  requires specific conditions to be exploited (such as an unusual...

In a sign that cybersecurity researchers continue to be under the radar of malicious actors, a proof-of-concept (PoC) has been discovered on GitHub, concealing a backdoor with a "crafty" persistence method. "In this instance, the PoC is a wolf in sheep's clothing, harboring malicious intent under the guise of a harmless learning tool," Uptycs researchers Nischay Hegde and Siddartha Malladi  said . "Operating as a downloader, it silently dumps and executes a Linux bash script, all the while disguising its operations as a kernel-level process." The  repository  masquerades as a PoC for  CVE-2023-35829 , a recently disclosed high-severity flaw in the Linux kernel. It has since been taken down, but not before it was forked 25 times.  Another PoC  shared by the same account, ChriSanders22, for  CVE-2023-20871 , a privilege escalation bug impacting VMware Fusion, was forked twice. Uptypcs also identified a  second GitHub profile  containing a b...

Details have emerged about a newly identified security flaw in the Linux kernel that could allow a user to gain elevated privileges on a target host. Dubbed  StackRot  ( CVE-2023-3269 , CVSS score: 7.8), the flaw impacts Linux versions 6.1 through 6.4. There is no evidence that the shortcoming has been exploited in the wild to date. "As StackRot is a Linux kernel vulnerability found in the memory management subsystem, it affects almost all kernel configurations and requires minimal capabilities to trigger," Peking University security researcher Ruihan Li  said . "However, it should be noted that maple nodes are freed using RCU callbacks, delaying the actual memory deallocation until after the RCU grace period. Consequently, exploiting this vulnerability is considered challenging." Following  responsible disclosure  on June 15, 2023, it has been  addressed  in stable versions 6.1.37, 6.3.11, and 6.4.1 as of July 1, 2023, after a two-week effort le...

Google on Monday introduced a new bug bounty program for its open source projects, offering payouts anywhere from $100 to $31,337 (a reference to  eleet or leet ) to secure the ecosystem from  supply chain attacks . Called the Open Source Software Vulnerability Rewards Program (OSS VRP), the offering is one of the first open source-specific vulnerability programs. With the tech giant the maintainer of major projects such as Angular, Bazel, Golang, Protocol Buffers, and Fuchsia, the program aims to reward vulnerability discoveries that could otherwise have a significant impact on the larger open source landscape.  Other projects managed by Google and hosted on public repositories such as GitHub as well as the third-party dependencies that are included in those projects are also eligible. Submissions  from bug hunters are expected to meet the following criteria - Vulnerabilities that lead to supply chain compromise Design issues that cause product vulnerabilit...

Details of an eight-year-old security vulnerability in the Linux kernel have emerged that the researchers say is "as nasty as Dirty Pipe." Dubbed  DirtyCred  by a group of academics from Northwestern University, the security weakness exploits a previously unknown flaw ( CVE-2022-2588 ) to escalate privileges to the maximum level. "DirtyCred is a kernel exploitation concept that swaps unprivileged  kernel credentials  with privileged ones to escalate privilege," researchers Zhenpeng Lin, Yuhang Wu, and Xinyu Xing noted. "Instead of overwriting any critical data fields on kernel heap, DirtyCred abuses the heap memory reuse mechanism to get privileged." This entails three steps - Free an in-use unprivileged credential with the vulnerability Allocate privileged credentials in the freed memory slot by triggering a privileged userspace process such as su, mount, or sshd Operate as a privileged user The novel exploitation method, according to the resea...

A new covert Linux kernel rootkit named  Syslogk  has been spotted under development in the wild and cloaking a malicious payload that can be remotely commandeered by an adversary using a  magic network traffic packet . "The Syslogk rootkit is heavily based on Adore-Ng but incorporates new functionalities making the user-mode application and the kernel rootkit hard to detect," Avast security researchers David Álvarez and Jan Neduchal  said  in a report published Monday. Adore-Ng, an  open-source rootkit  available since 2004, equips the attacker with full control over a compromised system. It also facilitates hiding processes as well as custom malicious artifacts, files, and even the kernel module, making it harder to detect. "The module starts by hooking itself into various file systems. It digs up the inode for the root filesystem, and replaces that inode's  readdir()  function pointer with one of its own," LWN.net  noted  at...

Google has released monthly security patches for Android with fixes for 37 flaws across different components, one of which is a fix for an actively exploited Linux kernel vulnerability that came to light earlier this year. Tracked as  CVE-2021-22600  (CVSS score: 7.8), the vulnerability is ranked "High" for severity and could be exploited by a local user to escalate privileges or deny service. The issue relates to a  double-free vulnerability  residing in the  Packet  network protocol implementation in the Linux kernel that could cause memory corruption, potentially leading to denial-of-service or execution of arbitrary code. Patches were released by different Linux distributions, including  Debian ,  Red Hat ,  SUSE , and  Ubuntu  in December 2021 and January 2022. "There are indications that CVE-2021-22600 may be under limited, targeted exploitation," Google  noted  in its Android Security Bulletin for May 2022. Sp...

Network-attached storage (NAS) appliance maker QNAP on Monday warned of a recently disclosed Linux vulnerability affecting its devices that could be abused to elevate privileges and gain control of affected systems. "A local privilege escalation vulnerability, also known as 'Dirty Pipe,' has been reported to affect the Linux kernel on QNAP NAS running QTS 5.0.x and QuTS hero h5.0.x," the company  said . "If exploited, this vulnerability allows an unprivileged user to gain administrator privileges and inject malicious code." The Taiwanese firm said it's continuing to thoroughly  investigate its product line  for the vulnerability and that QNAP NAS devices running QTS versions 4.x are immune to the Dirty Pipe flaw. Tracked as  CVE-2022-0847  (CVSS score: 7.8), the shortcoming resides in the Linux kernel that could permit an attacker to overwrite arbitrary data into any read-only files and allow for a complete takeover of vulnerable machines. "A...

A newly disclosed security flaw in the Linux kernel could be leveraged by a local adversary to gain elevated privileges on vulnerable systems to execute arbitrary code, escape containers, or induce a  kernel panic . Tracked as  CVE-2022-25636  (CVSS score: 7.8), the vulnerability impacts Linux kernel versions 5.4 through 5.6.10 and is a result of a heap out-of-bounds write in the netfilter subcomponent in the kernel. The issue was  discovered  by Nick Gregory, a senior threat researcher at Sophos. "This flaw allows a local attacker with a user account on the system to gain access to out-of-bounds memory, leading to a system crash or a privilege escalation threat," Red Hat  said  in an advisory published on February 22, 2022. Similar alerts have been released by  Debian ,  Oracle Linux ,  SUSE , and  Ubuntu . Netfilter is a  framework  provided by the Linux kernel that enables various networking-related operations, inc...

Linux distributions are in the process of issuing patches to address a newly disclosed security vulnerability in the kernel that could allow an attacker to overwrite arbitrary data into any read-only files and allow for a complete takeover of affected systems. Dubbed " Dirty Pipe " (CVE-2022-0847, CVSS score: 7.8) by IONOS software developer Max Kellermann, the flaw "leads to privilege escalation because unprivileged processes can inject code into root processes." Kellermann said the bug was discovered after digging into a support issue raised by one of the customers of the cloud and hosting provider that concerned a case of a "surprising kind of corruption" affecting web server access logs. The Linux kernel flaw is said to have existed since  version 5.8 , with the vulnerability sharing similarities to that of  Dirty Cow  (CVE-2016-5195), which came to light in October 2016. "A flaw was found in the way the 'flags' member of the new pip...

Cybersecurity researchers have disclosed a security flaw in the Linux Kernel's Transparent Inter Process Communication ( TIPC ) module that could potentially be leveraged both locally as well as remotely to execute arbitrary code within the kernel and take control of vulnerable machines. Tracked as CVE-2021-43267 (CVSS score: 9.8), the heap overflow vulnerability "can be exploited locally or remotely within a network to gain kernel privileges, and would allow an attacker to compromise the entire system," cybersecurity firm SentinelOne  said  in a report published today and shared with The Hacker News. TIPC is a transport layer  protocol   designed  for nodes running in dynamic cluster environments to reliably communicate with each other in a manner that's more efficient and fault-tolerant than other protocols such as TCP. The vulnerability identified by SentinelOne has to do with insufficient validation of user-supplied sizes for a new message type called "...

Google security researchers are warning of a new set of zero-click vulnerabilities in the Linux Bluetooth software stack that can allow a nearby unauthenticated, remote attacker to execute arbitrary code with kernel privileges on vulnerable devices. According to security engineer  Andy Nguyen , the three flaws — collectively called BleedingTooth — reside in the open-source  BlueZ  protocol stack that offers support for many of the core Bluetooth layers and protocols for Linux-based systems such as laptops and IoT devices. The first and the most severe is a heap-based type confusion ( CVE-2020-12351 , CVSS score 8.3) affecting Linux kernel 4.8 and higher and is present in the Logical Link Control and Adaptation Protocol ( L2CAP ) of the Bluetooth standard, which provides multiplexing of data between different higher layer protocols. "A remote attacker in short distance knowing the victim's [Bluetooth device] address can send a malicious l2cap packet and cause denial ...

Google has added a new security feature to the latest Linux kernels for Android devices to prevent it against code reuse attacks that allow attackers to achieve arbitrary code execution by exploiting control-flow hijacking vulnerabilities. In code reuse attacks, attackers exploit memory corruption bugs (buffer overflows, type confusion, or integer overflows) to take over code pointers stored in memory and repurpose existing code in a way that directs control flow of their choice, resulting in a malicious action. Since Android has a lot of mitigation to prevent direct code injection into its kernel, this code reuse method is particularly popular among hackers to gain code execution with the kernel because of the huge number of function pointers it uses. In an attempt to prevent this attack, Google has now added support for LLVM's Control Flow Integrity (CFI) to Android's kernel as a measure for detecting unusual behaviors of attackers trying to interfere or modify the contr...

A cybersecurity researcher with Google Project Zero has released the details, and a proof-of-concept (PoC) exploit for a high severity vulnerability that exists in Linux kernel since kernel version 3.16 through 4.18.8. Discovered by white hat hacker Jann Horn, the kernel vulnerability (CVE-2018-17182) is a cache invalidation bug in the Linux memory management subsystem that leads to use-after-free vulnerability, which if exploited, could allow an attacker to gain root privileges on the targeted system. The use-after-free (UAF) vulnerabilities are a class of memory corruption bug that can be exploited by unprivileged users to corrupt or alter data in memory, enabling them to cause a denial of service (system crash) or escalate privileges to gain administrative access on a system. Linux Kernel Exploit Takes an Hour to Gain Root Access However, Horn says his PoC Linux kernel exploit made available to the public "takes about an hour to run before popping a root shell....

Security researchers have published the details and proof-of-concept (PoC) exploits of an integer overflow vulnerability in the Linux kernel that could allow an unprivileged user to gain superuser access to the targeted system. The vulnerability, discovered by cloud-based security and compliance solutions provider Qualys, which has been dubbed "Mutagen Astronomy," affects the kernel versions released between July 2007 and July 2017, impacting the Red Hat Enterprise Linux, CentOS, and Debian distributions. The Mutagen Astronomy vulnerability tracked as CVE-2018-14634, is a type of a local privilege escalation issue—one of the most common issues with operating systems as a whole—and exists in the Linux kernel's create_elf_tables() function that operates the memory tables. To successfully exploit this vulnerability, attackers need to have access to the targeted system and run their exploit that leads to a buffer overflow, thereby resulting in the execution of malici...

What just happened would definitely gonna surprise you. Linus Torvalds—father of the Linux open-source operating system—finally admitted his behavior towards other developers in the Linux community was hurting people and Linux. In a surprising move this weekend, Torvalds apologized for insulting and abusing other developers for almost three decades and took a break from the open-source software to work on his behavior. In an email to the Linux Kernel Mailing List (LKML) on Sunday, Torvalds said that he was confronted by people of the Linux community this week about his lifetime of not understanding emotions, and apologized for his personal behavior that has hurt people and possibly has driven some of them away from working in kernel development altogether. Torvalds wrote, "I need to change some of my behavior, and I want to apologize to the people that my personal behavior hurt and possibly drove away from kernel development entirely." "I am going to take ...

UPDATE: Researchers have finally disclosed complete technical details of two kernel side-channel attacks, Meltdown and Spectre — which affect not only Intel but also systems and devices running AMD, ARM processors —allowing attackers to steal sensitive data from the system memory. ____________ The first week of the new year has not yet been completed, and very soon a massive vulnerability is going to hit hundreds of millions of Windows, Linux, and Mac users worldwide. According to a blog post published yesterday, the core team of Linux kernel development has prepared a critical kernel update without releasing much information about the vulnerability. Multiple researchers on Twitter  confirmed that Intel processors (x86-64) have a severe hardware-level issue that could allow attackers to access protected kernel memory, which primarily includes information like passwords, login keys, and files cached from disk. The security patch implements kernel page-table isolation...