Stories with Tag Privilege Escalation

• One Bug Wasn't Enough: Escalating Twice Through SAP's Setuid Landscape

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  Posted: 2025-04-09 16:56:31

  Verbose tl;dr

  Researchers discovered a vulnerability chain in SAP systems allowing for privilege escalation. Initially, a missing authorization check in a specific diagnostic tool allowed an attacker with low privileges to execute operating system commands as the sapadm user. This wasn't sufficient for full control, so they then exploited a setuid binary, sapstartsrv, designed to switch users. By manipulating the binary's expected environment, they were able to execute commands as root, achieving complete system compromise. This highlights the danger of accumulated vulnerabilities, especially within complex systems employing setuid binaries, and underscores the need for thorough security assessments within SAP environments.

  This blog post by Anvil Secure details a complex vulnerability discovery within SAP systems, highlighting how multiple seemingly minor flaws can be chained together to achieve significant privilege escalation. The researchers began with a relatively low-impact vulnerability, a path traversal issue in the SAP Start Service script (startsap). This script, often configured with setuid root permissions, allows users to start and stop SAP systems. The discovered path traversal allowed malicious actors to manipulate log file locations, enabling them to overwrite arbitrary files on the system, albeit with the startsap user's permissions. While this initial vulnerability provided some control, it didn't grant root access directly.

  Recognizing that limited file overwrite capability could be a stepping stone, the researchers meticulously examined the SAP environment for other exploitable components. They discovered a custom SAP program, sapuxuserchk, also running with setuid root. This program, responsible for verifying user existence within the SAP system, suffered from two key weaknesses. First, it dynamically loaded shared libraries. Second, its search path for these libraries included a user-writable directory. By strategically utilizing the initial path traversal vulnerability in startsap, the researchers could plant a malicious shared library in the searchable path. When sapuxuserchk subsequently executed, it unknowingly loaded the malicious library, granting the attackers root access.

  However, the researchers didn't stop there. They investigated further and uncovered yet another privilege escalation path stemming from the same initial path traversal flaw. This time, they targeted the sapcpe program, a central control interface within SAP systems, also frequently configured with setuid root privileges. This program featured a similar vulnerability to sapuxuserchk – a dynamic library loading mechanism susceptible to manipulation through a user-writable library path. By again leveraging the startsap path traversal, the researchers replaced a legitimate library used by sapcpe with their own malicious version, thus gaining a second independent route to root access.

  The post underscores the importance of defense-in-depth strategies. While individual vulnerabilities might seem insignificant in isolation, their combined impact can be devastating. The researchers emphasize that the prevalence of setuid binaries within the SAP landscape, combined with insecure library loading practices, creates a fertile ground for privilege escalation exploits. The blog post concludes by emphasizing the need for robust security practices, including careful scrutiny of setuid programs, secure library loading configurations, and adherence to the principle of least privilege. It also subtly advocates for the importance of vulnerability research and responsible disclosure, enabling vendors like SAP to address these weaknesses and improve the security posture of their systems.

  • SAP Security
  • Privilege Escalation
  • Setuid
  • exploitation
  • Vulnerability Research
  • Cybersecurity
  • Software Security
  • SAP Systems
  • Penetration Testing
  • Linux Security

  Summary of Comments ( 5 )
  https://news.ycombinator.com/item?id=43634408

  Verbose tl;dr

  Hacker News users discuss the complexity and potential security risks of SAP's extensive setuid landscape, highlighted by the blog post's detailed vulnerability chain. Several commenters express concern over the sheer number of setuid binaries, suggesting it represents a significant attack surface. Some doubt the practicality of the exploit due to required conditions, while others emphasize the importance of minimizing setuid usage in general. The discussion also touches on the challenges of managing such complex systems and the trade-offs between security and functionality in enterprise software. A few users question the blog post's disclosure timeline, suggesting a shorter timeframe would have been preferable.

  The Hacker News post titled "One Bug Wasn't Enough: Escalating Twice Through SAP's Setuid Landscape" has generated several comments discussing the complexities and security challenges inherent in SAP systems.

  One commenter highlights the sheer size and interconnected nature of SAP deployments, suggesting that this complexity contributes to the difficulty in securing these systems. They point out that even with dedicated security teams, vulnerabilities can persist due to the vast attack surface. This commenter also emphasizes the challenge of maintaining a balance between security and functionality, as overly restrictive security measures can hinder business operations.

  Another commenter focuses on the specific vulnerabilities mentioned in the article, discussing the implications of setuid binaries and the potential for privilege escalation. They delve into the technical details of the exploits, explaining how an attacker could leverage these vulnerabilities to gain unauthorized access to sensitive data or system resources. They also touch on the importance of proper patching and configuration management to mitigate such risks.

  Several commenters express concern over the prevalence of security issues in enterprise software like SAP. They discuss the potential financial and reputational damage that can result from successful attacks, and they urge organizations to prioritize security investments and best practices. One commenter even draws a parallel to the complexities and security challenges often seen in mainframe systems.

  A few commenters also discuss the challenges of applying traditional security practices to complex systems like SAP. They suggest that a more holistic and integrated approach is needed, incorporating elements of vulnerability management, incident response, and security awareness training. They also highlight the importance of collaboration between security teams and business stakeholders to ensure that security measures are aligned with business objectives.

  Finally, some comments offer practical advice for securing SAP systems, including recommendations for vulnerability scanning tools, security hardening guides, and penetration testing services. They also emphasize the importance of staying up-to-date on the latest security patches and advisories. One commenter specifically mentions the value of engaging with external security experts to conduct independent security assessments.

• Linux Kernel Defence Map – Security Hardening Concepts

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  Posted: 2025-04-05 22:16:54

  Verbose tl;dr

  The Linux Kernel Defence Map provides a comprehensive overview of security hardening mechanisms available within the Linux kernel. It categorizes these techniques into areas like memory management, access control, and exploit mitigation, visually mapping them to specific kernel subsystems and features. The map serves as a resource for understanding how various kernel configurations and security modules contribute to a robust and secure system, aiding in both defensive hardening and vulnerability research by illustrating the relationships between different protection layers. It aims to offer a practical guide for navigating the complex landscape of Linux kernel security.

  The Linux Kernel Defence Map, presented on GitHub by user a13xp0p0v, offers a comprehensive, visually-oriented guide to various security hardening techniques applicable to the Linux kernel. It serves as a roadmap for system administrators and security professionals seeking to enhance the security posture of their Linux systems by leveraging kernel-level defenses.

  The map categorizes these defenses into several key domains, reflecting different layers and aspects of kernel security. These include:

  • Kernel Self-Protection: This area focuses on mechanisms that protect the kernel itself from exploitation. Techniques listed encompass Kernel Address Space Layout Randomization (KASLR), which randomizes the location of kernel code in memory, and Kernel Page Table Isolation (KPTI/KAISER), which isolates user-space and kernel-space page tables to mitigate Meltdown-type vulnerabilities. It also covers Supervisor Mode Access Prevention (SMAP) and Supervisor Mode Execution Protection (SMEP), which restrict access and execution from supervisor mode to user-space memory, preventing certain types of privilege escalation attacks.

  • Memory Management Hardening: This domain deals with securing the kernel's memory management subsystem. It includes strategies like restricting memory allocations with SLAB_FREELIST_HARDENED, enabling memory tagging extensions like ARM Memory Tagging Extension (MTE), and implementing hardened usercopy functions to prevent vulnerabilities arising from copying data between user and kernel space.

  • Capability-Based Security: This section outlines the use of Linux capabilities, which provide a finer-grained alternative to traditional root privileges, allowing processes to have specific privileges without granting full administrative access. This helps limit the potential damage from compromised processes.

  • Namespaces and Seccomp: These features isolate processes from each other and the system, limiting their access to resources and system calls. Namespaces create isolated environments for processes, while Seccomp allows restricting the system calls a process can make. This restricts the attack surface available to a malicious process.

  • Security Modules: The map covers various security modules like SELinux, AppArmor, and TOMOYO Linux, which provide mandatory access control (MAC) frameworks. These modules enforce predefined security policies, restricting access to resources based on labels and rules, even for privileged processes. This adds an additional layer of security beyond traditional discretionary access control.

  • Cryptographic API Hardening: This area addresses securing cryptographic operations within the kernel. It highlights the use of cryptographic agility, enabling constant-time cryptographic algorithms to prevent timing attacks, and using a hardware security module (HSM) to offload sensitive cryptographic operations to a dedicated secure device.

  • Auditing and Intrusion Detection: This category covers mechanisms to monitor kernel activity and detect suspicious events. It includes the use of the audit subsystem for logging security-relevant events, and integrating kernel instrumentation with intrusion detection systems.

  • Exploit Mitigation Techniques: The map lists various exploit mitigation methods, like stack canaries, which detect stack overflows, and Shadow Stacks, which protect return addresses from modification. These techniques make it more difficult for attackers to exploit vulnerabilities.

  The Linux Kernel Defence Map provides a valuable overview, presenting these security hardening concepts in a structured and accessible format. It serves as a starting point for those looking to understand and implement kernel-level security measures, offering a broad perspective on the landscape of available techniques and guiding further research into specific areas of interest. However, it's crucial to note that security is a continuous process, and this map represents a snapshot of current best practices, not a complete or static solution. Continuous learning and adaptation are essential for maintaining a robust security posture.

  • Linux
  • Kernel
  • Security
  • Hardening
  • Defense
  • map
  • exploitation
  • Vulnerability
  • Mitigation
  • system calls
  • Privilege Escalation
  • Rootkit
  • Malware
  • Threat Modeling
  • Cybersecurity
  • Operating System
  • Open Source

  Summary of Comments ( 10 )
  https://news.ycombinator.com/item?id=43597264

  Verbose tl;dr

  Hacker News users generally praised the Linux Kernel Defence Map for its comprehensiveness and visual clarity. Several commenters pointed out its value for both learning and as a quick reference for experienced kernel developers. Some suggested improvements, including adding more details on specific mitigations, expanding coverage to areas like user namespaces and eBPF, and potentially creating an interactive version. A few users discussed the project's scope, questioning the inclusion of certain features and debating the effectiveness of some mitigations. There was also a short discussion comparing the map to other security resources.

  The Hacker News post titled "Linux Kernel Defence Map – Security Hardening Concepts" generated several comments discussing the linked resource, a mind map visualizing various Linux kernel security hardening mechanisms.

  Several commenters praised the map for its comprehensive overview and visual appeal. One user described it as "extremely helpful" and appreciated the clear organization of complex information. Another lauded the project's "great work" and found it beneficial for both learning and review. The visual nature of the map was highlighted as a key strength, allowing users to quickly grasp the relationships between different security concepts.

  Some commenters focused on the map's practicality and usefulness. One suggested using it for security audits or as a reference during incident response. Another highlighted its potential as a learning tool, allowing users to delve deeper into specific areas based on their interests. The ability to see the interconnectedness of various security mechanisms was also mentioned as valuable for developing a holistic understanding of kernel security.

  Several comments discussed specific aspects of kernel security and their representation in the map. Discussion arose around kernel self-protection mechanisms and their limitations. One commenter pointed out the trade-off between security and performance, emphasizing that implementing every hardening technique could have performance implications. Another mentioned the importance of keeping the map updated as new security features are introduced in the kernel. The inclusion of specific kernel modules and their functionalities was also discussed.

  A few commenters suggested improvements or additions to the map. One recommended including links to relevant documentation or resources for each security mechanism. Another proposed adding a section on eBPF-based security tools. The possibility of creating an interactive version of the map was also mentioned.

  Overall, the comments reflected a positive reception of the Linux Kernel Defence Map. Commenters appreciated its comprehensive nature, visual clarity, and practical value for both learning and professional use. While some suggestions for improvements were made, the overall consensus was that the map provides a valuable resource for anyone interested in understanding and enhancing Linux kernel security.

• Susctl CVE-2024-54507: A particularly 'sus' sysctl in the XNU kernel

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  Posted: 2025-01-23 22:37:57

  Verbose tl;dr

  A vulnerability (CVE-2024-54507) was discovered in the XNU kernel, affecting macOS and iOS, which allows malicious actors to leak kernel memory. The flaw resides in the sysctl interface, specifically the kern.hv_vmm_vcpu_state handler. This handler failed to properly validate the size of the buffer provided by the user, resulting in an out-of-bounds read. By crafting a request with a larger buffer than expected, an attacker could read data beyond the intended memory region, potentially exposing sensitive kernel information. This vulnerability was patched by Apple in October 2024 and is relatively simple to exploit.

  The blog post by Jann Horn, titled "Susctl CVE-2024-54507: A particularly 'sus' sysctl in the XNU kernel," details a vulnerability (CVE-2024-54507) discovered in Apple's XNU kernel, impacting macOS and iOS. This vulnerability stems from improper handling of the kern.sysctlbyname sysctl, specifically when dealing with nested structures within sysctl MIBs (Management Information Bases).

  Horn explains that kern.sysctlbyname allows userspace programs to access kernel data structures by specifying a name-based path, akin to navigating a file system. The issue arises when a MIB entry points to a structure containing further nested structures or pointers. Normally, sysctlbyname should only allow access to the top-level structure specified in the MIB. However, the flawed implementation permitted traversing deeper into these nested structures by simply appending the names of the inner members to the sysctl name, even if those inner members weren't explicitly exposed by any MIB entry.

  This effectively bypassed intended access restrictions, granting access to kernel memory regions that should have been inaccessible to userspace. The specific example provided in the post demonstrates reading the version field of an embedded os_unfair_lock structure within another structure exposed via a sysctl. Although this example only disclosed kernel version information, Horn highlights that this vulnerability could potentially be exploited to leak more sensitive data or even achieve arbitrary memory read, depending on the structures accessible through vulnerable sysctl entries.

  The post delves into the technical details of the vulnerability, explaining how the kernel's internal sysctl_name function mishandled the traversal of these nested structures. It misinterprets the presence of a sub-structure within a returned buffer as an indicator that further traversal is permissible, even if no MIB entry exists for the sub-structure. This logic flaw allows an attacker to construct arbitrary paths by appending the names of nested members, essentially crafting a "fake" MIB entry on the fly.

  Horn's analysis includes a detailed breakdown of the vulnerable code path within the kernel, illustrating the faulty logic. He further illustrates the exploitation process by showcasing a proof-of-concept code snippet that successfully reads the version field of the nested os_unfair_lock structure. The post concludes by mentioning that Apple has addressed this vulnerability in their security updates and encourages users to update their systems. The fix likely involves restricting traversal beyond the top-level structure specified in the MIB, preventing access to nested members not explicitly exposed.

  • CVE-2024-54507
  • XNU
  • Kernel
  • macOS
  • iOS
  • Vulnerability
  • Security
  • Exploit
  • Sysctl
  • Privilege Escalation
  • Kernel Exploit
  • Mac Security
  • iOS Security

  Summary of Comments ( 8 )
  https://news.ycombinator.com/item?id=42808801

  Verbose tl;dr

  Hacker News commenters discuss the CVE-2024-54507 vulnerability, focusing on the unusual nature of the vulnerable sysctl and the potential implications. Several express surprise at the existence of a sysctl that directly modifies kernel memory, questioning why such a mechanism exists and speculating about its intended purpose. Some highlight the severity of the vulnerability, emphasizing the ease of exploitation and the potential for privilege escalation. Others note the fortunate aspect of the bug manifesting as a kernel panic rather than silent memory corruption, making detection easier. The limited practical impact due to System Integrity Protection (SIP) is also mentioned, alongside the difficulty of exploiting the vulnerability remotely. A few commenters also delve into the technical details of the exploit, discussing the specific memory manipulation involved and the resulting kernel crash. The overall sentiment reflects concern about the unusual nature of the vulnerability and its potential implications, even with the mitigating factors.

  The Hacker News post discussing the CVE-2024-54507 vulnerability in the XNU kernel, titled "Susctl CVE-2024-54507: A particularly 'sus' sysctl in the XNU kernel," has generated several comments.

  Many commenters focus on the unusual nature of the vulnerability and its exploitation. One commenter points out the irony of a vulnerability existing in a mechanism designed to improve security, specifically the sysctl interface intended for secure configuration adjustments. They express surprise that such a fundamental component could be susceptible to this type of issue.

  Another commenter delves into the technical details of the exploit, highlighting the unexpected behavior of the sysctl handler. They discuss how the vulnerability arises from an incorrect handling of specific input, leading to a kernel panic. The comment emphasizes the severity of the issue, as it can be triggered remotely, potentially allowing for denial-of-service attacks.

  Several commenters also discuss the implications of the vulnerability for Apple users. Some express concern about the potential impact on macOS and iOS devices, given the widespread use of the XNU kernel. Others raise questions about the timeline for a patch and the potential for exploitation in the wild.

  A few comments touch on the broader security implications of this type of vulnerability. One commenter notes the increasing complexity of modern operating systems and the challenges of ensuring their security. They suggest that this vulnerability highlights the need for more robust security testing and validation processes.

  Some of the more technically inclined comments delve into the specifics of the kernel code and the mechanisms that led to the vulnerability. These comments offer insights into the inner workings of the XNU kernel and provide a deeper understanding of the exploit's technical details.

  A couple of commenters also discuss the responsible disclosure process and commend the researchers for reporting the vulnerability to Apple before publicly disclosing it. They emphasize the importance of responsible disclosure in mitigating the potential impact of security vulnerabilities.

  Overall, the comments on the Hacker News post reflect a mixture of surprise, concern, and technical analysis. The commenters acknowledge the severity of the vulnerability and its potential impact on Apple users, while also delving into the technical intricacies of the exploit and its implications for kernel security.