An operator precedence bug in the kernel results in a scenario where a buffer overflow causes attacker-controlled data to overwrite adjacent execve(2) argument buffers. The bug may be exploitable by an unprivileged user to obtain superuser privileges.

FreeBSD: Input Validation Flaw allows local users to gain elevated privileges

grub2-bhyve, as used in FreeBSD bhyve before revision 525916 2020-02-12, mishandles font loading by a guest through a grub2.cfg file, leading to a buffer overflow.

In FreeBSD 12.1-STABLE before r352509, 11.3-STABLE before r352509, and 11.3-RELEASE before p9, an unprivileged local user can trigger a use-after-free situation due to improper checking in SCTP when an application tries to update an SCTP-AUTH shared key.

ld.so in FreeBSD, NetBSD, and possibly other BSD distributions does not remove certain harmful environment variables, which allows local users to gain privileges by passing certain environment variables to loading processes. NOTE: this issue has been disputed by a third party, stating that it is the responsibility of the application to properly sanitize the environment

Handlers for *_CFG_PAGE read / write ioctls in the mpr, mps, and mpt drivers allocated a buffer of a caller-specified size, but copied to it a fixed size header. Other heap content would be overwritten if the specified size was too small. Users with access to the mpr, mps or mpt device node may overwrite heap data, potentially resulting in privilege escalation. Note that the device node is only accessible to root and members of the operator group.

The kernel handler for IPV6_MSFILTER dropped a serializing lock in order to copy the source-filter list from userspace, then reacquired the lock. During this window another thread could free the multicast filter structure, leaving the handler with a stale pointer to freed memory. An unprivileged local user can exploit this use-after-free to escalate privileges.

The ELF image activator cleared per-process ASLR preference flags for setuid binaries after the code that computes the PIE base address, rather than before. As a result, a user-requested ASLR disable was still in effect at the point where the base address was chosen. An unprivileged local user can disable ASLR for a setuid PIE binary by calling procctl(2) before execve(2). This makes exploitation of any separate memory corruption vulnerability in that binary significantly easier.

The CONS_HISTORY ioctl handler did not adequately validate the requested history size. A large value caused an integer overflow in the buffer size calculation, resulting in a heap allocation smaller than expected. Subsequent initialization of the buffer wrote beyond the end of the allocation. An unprivileged local user with access to a vt(4) device can trigger an out-of-bounds write in the kernel, potentially escalating privileges.

The setcred(2) system call is only available to privileged users. However, before the privilege level of the caller is checked, the user-supplied list of supplementary groups is copied into a fixed-size kernel stack buffer without first validating its length. If the supplied list exceeds the capacity of that buffer, a stack buffer overflow occurs. Because the bounds check on the supplementary groups list occurs after the kernel stack buffer has already been written, an unprivileged local user may trigger the overflow without holding any special privilege. Successful exploitation may allow an attacker to execute arbitrary code in the context of the kernel, allowing an unprivileged local user to gain elevated privileges on the affected system.

A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object. In the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability. The use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges.

The KTLS receive path decrypted each record in place, assuming that the mbufs holding received data were anonymous and safe to modify. This assumption does not hold for data placed on a socket by sendfile(2), which can reference file-backed memory directly through non-anonymous M_EXTPG pages or EXT_SFBUF mbufs. When the sender transmits such data over a loopback connection without enabling KTLS on the transmit side, the file-backed mbufs reach the receiver's decryption path unchanged. Decrypting a record in place then overwrites the backing file's page cache instead of a private copy of the data. An unprivileged local user who can read a file can overwrite its contents with data of their choosing by sending the file over a loopback connection on which they have enabled KTLS receive. The write modifies the page cache directly, so it bypasses file flags such as schg and is written back to disk. By overwriting a setuid binary or other trusted file, a local user can escalate privileges, potentially gaining full control of the affected system.

dsp_mmap_single() validated the requested mapping by checking the sum of the user-supplied offset and length against the buffer size. This addition could overflow, so that a large offset and length wrapped around and passed the check. The offset was then narrowed from 64 to 32 bits when converted to a buffer address, yielding a mapping that extended past the audio buffer into unrelated kernel memory. The /dev/dsp device nodes are world-accessible by default. On a system with an audio device, either issue allows an unprivileged local user to read and write kernel memory, which can be used to escalate privileges, potentially gaining full control of the affected system. At a minimum, an attacker can crash the kernel, resulting in a Denial of Service (DoS).

FreeBSD 5.x to 5.4 on AMD64 does not properly initialize the IO permission bitmap used to allow user access to certain hardware, which allows local users to bypass intended access restrictions to cause a denial of service, obtain sensitive information, and possibly gain privileges.

When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, can trigger stack corruption. If the target application is setuid-root, then this could be used to elevate local privileges.

grub2-bhyve, as used in FreeBSD bhyve before revision 525916 2020-02-12, does not validate the address provided as part of a memrw command (read_* or write_*) by a guest through a grub2.cfg file. This allows an untrusted guest to perform arbitrary read or write operations in the context of the grub-bhyve process, resulting in code execution as root on the host OS.

Local user gains root privileges via buffer overflow in rdist, via expstr() function.

In FreeBSD 13.0-STABLE before n245050, 12.2-STABLE before r369525, 13.0-RC4 before p0, and 12.2-RELEASE before p6, listening socket accept filters implementing the accf_create callback incorrectly freed a process supplied argument string. Additional operations on the socket can lead to a double free or use after free.

In FreeBSD 13.0-STABLE before n246941-20f96f215562, 12.2-STABLE before r370400, 11.4-STABLE before r370399, 13.0-RELEASE before p4, 12.2-RELEASE before p10, and 11.4-RELEASE before p13, certain VirtIO-based device models in bhyve failed to handle errors when fetching I/O descriptors. A malicious guest may cause the device model to operate on uninitialized I/O vectors leading to memory corruption, crashing of the bhyve process, and possibly arbitrary code execution in the bhyve process.

Weak file permissions applied to the Aviatrix VPN Client through 2.2.10 installation directory on Windows and Linux allow a local attacker to execute arbitrary code by gaining elevated privileges through file modifications.

In FreeBSD 13.0-STABLE before n245118, 12.2-STABLE before r369552, 11.4-STABLE before r369560, 13.0-RC5 before p1, 12.2-RELEASE before p6, and 11.4-RELEASE before p9, a superuser inside a FreeBSD jail configured with the non-default allow.mount permission could cause a race condition between the lookup of ".." and remounting a filesystem, allowing access to filesystem hierarchy outside of the jail.

OpenZFS before 2.0.0-rc1, when used on FreeBSD, misinterprets group permissions as user permissions, as demonstrated by mode 0770 being equivalent to mode 0777.

OpenZFS before 2.0.0-rc1, when used on FreeBSD, allows execute permissions for all directories.

In FreeBSD 12.0-STABLE before r349805, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r349806, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, code which handles close of a descriptor created by posix_openpt fails to undo a signal configuration. This causes an incorrect signal to be raised leading to a write after free of kernel memory allowing a malicious user to gain root privileges or escape a jail.

In FreeBSD 12.0-STABLE before r350261, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r350263, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, system calls operating on file descriptors as part of mqueuefs did not properly release the reference allowing a malicious user to overflow the counter allowing access to files, directories, and sockets opened by processes owned by other users.

In FreeBSD 12.0-STABLE before r350222, 12.0-RELEASE before 12.0-RELEASE-p8, 11.3-STABLE before r350223, 11.3-RELEASE before 11.3-RELEASE-p1, and 11.2-RELEASE before 11.2-RELEASE-p12, rights transmitted over a domain socket did not properly release a reference on transmission error allowing a malicious user to cause the reference counter to wrap, forcing a free event. This could allow a malicious local user to gain root privileges or escape from a jail.

The virtio_vq_recordon function is subject to a time-of-check to time-of-use (TOCTOU) race condition.

In FreeBSD 12.1-STABLE before r363918, 12.1-RELEASE before p8, 11.4-STABLE before r363919, 11.4-RELEASE before p2, and 11.3-RELEASE before p12, the sendmsg system call in the compat32 subsystem on 64-bit platforms has a time-of-check to time-of-use vulnerability allowing a mailcious userspace program to modify control message headers after they were validation.

Improper privilege management in the log rotation mechanism of the Skylight Workspace Config Service in Amazon WorkSpaces for Windows before 2.6.2034.0 allows a local non-admin authenticated user to place arbitrary files into arbitrary locations bypassing file system permission protections, leading to local privilege escalation to SYSTEM.

Memory corruption while submitting blob data to kernel space though IOCTL.

Memory corruption when using Virtual cdm (Camera Data Mover) to write registers.

Memory corruption while processing INIT and multimode invoke IOCTL calls on FastRPC.

Time-of-check time-of-use race condition in the UEFI firmware SmiVariable driver for the Intel(R) Server D50DNP and M50FCP boards may allow a privileged user to enable escalation of privilege via local access.

Time-of-check Time-of-use race condition for some Intel(R) Connectivity Performance Suite software installers before version 40.24.11210 may allow an authenticated user to potentially enable escalation of privilege via local access.

Double fetch in sandbox kernel driver in Avast/AVG Antivirus <25.3  on windows allows local attacker to escalate privelages via pool overflow.

The Zoom Rooms Installer for Windows prior to 5.12.6 contains a local privilege escalation vulnerability. A local low-privileged user could exploit this vulnerability during the install process to escalate their privileges to the SYSTEM user.

Memory Corruption when accessing shared buffers without validation of concurrent user-mode input modifications.

A time-of-check time-of-use (TOCTOU) race condition was found in the abrt-dbus D-Bus service's SetElement method. Between dump directory creation and post-create event execution, any local user can call SetElement to write arbitrary text files into the root-owned dump directory, bypassing package validation and allowing crashes of unpackaged binaries to survive post-create processing.

This vulnerability allows local attackers to escalate privileges on affected installations of Parallels Access 6.5.4 (39316) Agent. An attacker must first obtain the ability to execute low-privileged code on the target host system in order to exploit this vulnerability. The specific flaw exists within the Parallels service. By creating a symbolic link, an attacker can abuse the service to execute a file. An attacker can leverage this vulnerability to escalate privileges and execute arbitrary code in the context of root. Was ZDI-CAN-16134.

A Time-of-Check to Time-of-Use (TOCTOU) vulnerability has been identified in the driver of the NDD Print solution, which could allow an unprivileged user to exploit this flaw and gain SYSTEM-level access on the device. The vulnerability affects version 5.24.3 and before of the software.

In UsbCoreDxe, tampering with the contents of the USB working buffer using DMA while certain USB transactions are in process leads to a TOCTOU problem that could be used by an attacker to cause SMRAM corruption and escalation of privileges The UsbCoreDxe module creates a working buffer for USB transactions outside of SMRAM. The code which uses can be inside of SMM, making the working buffer untrusted input. The buffer can be corrupted by DMA transfers. The SMM code code attempts to sanitize pointers to ensure all pointers refer to the working buffer, but when a pointer is not found in the list of pointers to sanitize, the current action is not aborted, leading to undefined behavior. This issue was discovered by Insyde engineering based on the general description provided by Intel's iSTARE group. Fixed in: Kernel 5.0: Version 05.09. 21 Kernel 5.1: Version 05.17.21 Kernel 5.2: Version 05.27.21 Kernel 5.3: Version 05.36.21 Kernel 5.4: Version 05.44.21 Kernel 5.5: Version 05.52.21 https://www.insyde.com/security-pledge/SA-2022063

APTIOV contains a vulnerability in BIOS where an attacker may cause a Time-of-check Time-of-use (TOCTOU) Race Condition by local means. Successful exploitation of this vulnerability may lead to arbitrary code execution.

Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.

Dell ThinOS version 2408 contains a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability. A low privileged attacker with local access could potentially exploit this vulnerability, leading to Elevation of Privileges.

Memory corruption may occur while processing message from frontend during allocation.

Memory corruption may occur in keyboard virtual device due to guest VM interaction.