Qualys discovered a size_t-to-int conversion vulnerability in the Linux kernel's filesystem layer: by creating, mounting, and deleting a deep directory structure whose total path length exceeds 1GB, an unprivileged local attacker can write the 10-byte string "//deleted" to an offset of exactly -2GB-10B below the beginning of a vmalloc()ated kernel buffer. They successfully exploited this uncontrolled out-of-bounds write, and obtained full root privileges on default installations of Ubuntu 20.04, Ubuntu 20.10, Ubuntu 21.04, Debian 11, and Fedora 34 Workstation; other Linux distributions are certainly vulnerable, and probably exploitable. A basic proof of concept (a crasher) is attached to this advisory.
2739ab8c7448e7ea41f28d5e97efa32aA heap based buffer overflow exists in the sudo command line utility that can be exploited by a local attacker to gain elevated privileges. The vulnerability was introduced in July of 2011 and affects version 1.8.2 through 1.8.31p2 as well as 1.9.0 through 1.9.5p1 in their default configurations. The technique used by this implementation leverages the overflow to overwrite a service_user struct in memory to reference an attacker controlled library which results in it being loaded with the elevated privileges held by sudo.
5a520123546e73d450b7fef8df23c9deQualys has released extensive research details regarding a heap-based buffer overflow vulnerability in sudo. The issue was introduced in July 2011 (commit 8255ed69), and affects all legacy versions from 1.8.2 to 1.8.31p2 and all stable versions from 1.9.0 to 1.9.5p1, in their default configuration.
0c2a538435159ba2390cd0a028f6de4cQualys has released their local privilege escalation and remote code execution exploit for qmail that leverages the vulnerability as described in CVE-2005-1513.
918f10fb453026a4eef569943c62c387In 2005, three vulnerabilities were discovered in qmail but were never fixed because they were believed to be unexploitable in a default installation. Qualys recently re-discovered these vulnerabilities and were able to exploit one of them remotely in a default installation.
f669ab533f30c6f109eb83ceceabfd6cThis Metasploit module exploits an out-of-bounds read of an attacker-controlled string in OpenSMTPD's MTA implementation to execute a command as the root or nobody user, depending on the kind of grammar OpenSMTPD uses.
229752794172ef51ce4a73f8eb7d3948Qualys discovered a vulnerability in OpenSMTPD, OpenBSD's mail server. This vulnerability, an out-of-bounds read introduced in December 2015, is exploitable remotely and leads to the execution of arbitrary shell commands.
a2c12d92302d9d428325ff4fc6f243baQualys discovered a minor vulnerability in OpenSMTPD, OpenBSD's mail server. An unprivileged local attacker can read the first line of an arbitrary file (for example, root's password hash in /etc/master.passwd) or the entire contents of another user's file (if this file and /var/spool/smtpd/ are on the same filesystem). A proof of concept exploit is included in this archive.
56573da09e74bf6cccffa5506e80c6d3This Metasploit module exploits a command injection in the MAIL FROM field during SMTP interaction with OpenSMTPD to execute code as the root user.
2b9fdae42ead941fa800754cf08e9965OpenSMTPD version 6.6.2 remote code execution exploit.
720e1a175b5cc8abf21ab6dbeb5c21e7Qualys discovered a vulnerability in OpenSMTPD, OpenBSD's mail server. This vulnerability is exploitable since May 2018 (commit a8e222352f, "switch smtpd to new grammar") and allows an attacker to execute arbitrary shell commands, as root.
a167abd4844564a180e18a022a305764This Metasploit module exploits a vulnerability in the OpenBSD ld.so dynamic loader (CVE-2019-19726). The _dl_getenv() function fails to reset the LD_LIBRARY_PATH environment variable when set with approximately ARG_MAX colons. This can be abused to load libutil.so from an untrusted path, using LD_LIBRARY_PATH in combination with the chpass set-uid executable, resulting in privileged code execution. This module has been tested successfully on OpenBSD 6.1 (amd64) and OpenBSD 6.6 (amd64).
0a972f77813616f87fc79b2ebe062ffbQualys discovered a local privilege escalation in OpenBSD's dynamic loader (ld.so). This vulnerability is exploitable in the default installation (via the set-user-ID executable chpass or passwd) and yields full root privileges. They developed a simple proof of concept and successfully tested it against OpenBSD 6.6 (the current release), 6.5, 6.2, and 6.1, on both amd64 and i386; other releases and architectures are probably also exploitable.
5cd25d74e467c8f83e9ece30c0c6b982Qualys discovered a remote command execution vulnerability in Exim versions 4.87 to 4.91.
bad52ccc6a1c8c1cead9b91ad808d490This is the systemd-journald exploit produced by Qualys that demonstrates the vulnerabilities as highlighted in CVE-2018-16865 and CVE-2018-16866.
3e54ce0e261472361d1e307593f752a3This is a thorough analysis of how Qualys approached exploiting three vulnerabilities in systemd-journald. Although they have not released formal exploits yet, they detail in here is useful in understanding the flaws.
5e1ba71c0b7e7dbafebb77bbd2703730This Metasploit module exploits a vulnerability in RSH on unpatched Solaris systems which allows users to gain root privileges. The stack guard page on unpatched Solaris systems is of insufficient size to prevent collisions between the stack and heap memory, aka Stack Clash. This Metasploit module uploads and executes Qualys' Solaris_rsh.c exploit, which exploits a vulnerability in RSH to bypass the stack guard page to write to the stack and create a SUID root shell. This Metasploit module has offsets for Solaris versions 11.1 (x86) and Solaris 11.3 (x86). Exploitation will usually complete within a few minutes using the default number of worker threads (10). Occasionally, exploitation will fail. If the target system is vulnerable, usually re-running the exploit will be successful. This Metasploit module has been tested successfully on Solaris 11.1 (x86) and Solaris 11.3 (x86).
91b277586c77a3c37e33c0ac990f0483Linux suffers from an integer overflow vulnerability in create_elf_tables(). Multiple exploits provided.
5ec6314ab72881f0d67179acf1811540This Metasploit module attempts to gain root privileges on Red Hat based Linux systems, including RHEL, Fedora and CentOS, by exploiting a newline injection vulnerability in libuser and userhelper versions prior to 0.56.13-8 and version 0.60 before 0.60-7. This Metasploit module makes use of the roothelper.c exploit from Qualys to insert a new user with UID=0 in /etc/passwd. Note, the password for the current user is required by userhelper. Note, on some systems, such as Fedora 11, the user entry for the current user in /etc/passwd will become corrupted and exploitation will fail. This Metasploit module has been tested successfully on libuser packaged versions 0.56.13-4.el6 on CentOS 6.0 (x86_64); 0.56.13-5.el6 on CentOS 6.5 (x86_64); 0.60-5.el7 on CentOS 7.1-1503 (x86_64); 0.56.16-1.fc13 on Fedora 13 (i686); 0.59-1.fc19 on Fedora Desktop 19 (x86_64); 0.60-3.fc20 on Fedora Desktop 20 (x86_64); 0.60-6.fc21 on Fedora Desktop 21 (x86_64); 0.60-6.fc22 on Fedora Desktop 22 (x86_64); 0.56.13-5.el6 on Red Hat 6.6 (x86_64); and 0.60-5.el7 on Red Hat 7.0 (x86_64). RHEL 5 is vulnerable, however the installed version of glibc (2.5) is missing various functions required by roothelper.c.
29f14e9f5067bd0c43af11f1008beb02Qualys has discovered a memory leak and a buffer overflow in the dynamic loader (ld.so) of the GNU C Library (glibc).
627d9c13d012677a6feb6b4514cbb8e3A Linux PIE/stack corruption vulnerability exists. Most notably, all versions of CentOS 7 before 1708 (released on September 13, 2017), all versions of Red Hat Enterprise Linux 7 before 7.4 (released on August 1, 2017), and all versions of CentOS 6 and Red Hat Enterprise Linux 6 are exploitable.
b53db8644bb756103fde5373b019b1c1Since version 5.4 (released on March 8, 2010), the OpenSSH client supports an undocumented feature called roaming: if the connection to an SSH server breaks unexpectedly, and if the server supports roaming as well, the client is able to reconnect to the server and resume the suspended SSH session. Although roaming is not supported by the OpenSSH server, it is enabled by default in the OpenSSH client, and contains two vulnerabilities that can be exploited by a malicious SSH server (or a trusted but compromised server): an information leak (memory disclosure), and a buffer overflow (heap-based).
2360520b5690a162d17aeb52bbfce9f6Qualys discovered various vulnerabilities in LibreSSL. These include a memory leak and a buffer overflow.
a09c98183d166108c5dbf9105951954aQualys discovered various vulnerabilities in OpenSMTPD. These include, but are not limited to, denial of service, buffer overflow, hardlink attack and use-after-free vulnerabilities.
20c4ffd499c1a6466cfce72f6b1c0a80The libuser library implements a standardized interface for manipulating and administering user and group accounts, and is installed by default on Linux distributions derived from Red Hat's codebase. During an internal code audit at Qualys, they discovered multiple libuser-related vulnerabilities that allow local users to perform denial-of-service and privilege-escalation attacks. As a proof of concept, they developed an unusual local root exploit against one of libuser's applications. Both the advisory and exploit are included in this post.
d10eb7969178d2c38456f40ec558206a
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