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.

An issue was discovered in all versions of PCManFM-Qt starting from 1.1.0. When a regular file's path is passed as a URI in an org.freedesktop.FileManager1.ShowFolders D-Bus method call, PCManFM-Qt delegates to a different program (based on the file type) without user confirmation. This could be used to achieve code execution or circumvent network namespace restrictions. NOTE: those outcomes are potentially unwanted by most users; however, the behavior of the product does comply with the applicable specification, and a simplistic solution (ensuring that the URI does not name a regular file) may have adverse consequences for I/O.

The newly introduced RecordUsage D-Bus method https://gitlab.freedesktop.org/pwithnall/malcontent/-/blob/0.14.0/libmalcontent-timer/child-timer-service.c in malcontent-timerd allows arbitrary users in the system to slowly fill up disk space in /var/lib/malcontent-timerd

The new upstream added a privileged D-Bus helper called plasmaloginauthhelper, which suffers from multiple issues, e.g.aA compromised plasmalogin service account can chown() arbitrary files in the system.

PackageKit is a a D-Bus abstraction layer that allows the user to manage packages in a secure way using a cross-distro, cross-architecture API. PackageKit between and including versions 1.0.2 and 1.3.4 is vulnerable to a time-of-check time-of-use (TOCTOU) race condition on transaction flags that allows unprivileged users to install packages as root and thus leads to a local privilege escalation. This is patched in version 1.3.5. A local unprivileged user can install arbitrary RPM packages as root, including executing RPM scriptlets, without authentication. The vulnerability is a TOCTOU race condition on `transaction->cached_transaction_flags` combined with a silent state-machine guard that discards illegal backward transitions while leaving corrupted flags in place. Three bugs exist in `src/pk-transaction.c`: 1. Unconditional flag overwrite (line 4036): `InstallFiles()` writes caller-supplied flags to `transaction->cached_transaction_flags` without checking whether the transaction has already been authorized/started. A second call blindly overwrites the flags even while the transaction is RUNNING. 2. Silent state-transition rejection (lines 873–882): `pk_transaction_set_state()` silently discards backward state transitions (e.g. `RUNNING` → `WAITING_FOR_AUTH`) but the flag overwrite at step 1 already happened. The transaction continues running with corrupted flags. 3. Late flag read at execution time (lines 2273–2277): The scheduler's idle callback reads cached_transaction_flags at dispatch time, not at authorization time. If flags were overwritten between authorization and execution, the backend sees the attacker's flags.

packagekit_project

Tmds.DBus provides .NET libraries for working with D-Bus from .NET. Tmds.DBus and Tmds.DBus.Protocol are vulnerable to malicious D-Bus peers. A peer on the same bus can spoof signals by impersonating the owner of a well-known name, exhaust system resources or cause file descriptor spillover by sending messages with an excessive number of Unix file descriptors, and crash the application by sending malformed message bodies that cause unhandled exceptions on the SynchronizationContext. This vulnerability is fixed in Tmds.DBus 0.92.0 and Tmds.DBus.Protocol 0.92.0 and 0.21.3.

xdg-dbus-proxy is a filtering proxy for D-Bus connections. Prior to 0.1.7, a policy parser vulnerability allows bypassing eavesdrop restrictions. The proxy checks for eavesdrop=true in policy rules but fails to handle eavesdrop ='true' (with a space before the equals sign) and similar cases. Clients can intercept D-Bus messages they should not have access to. This vulnerability is fixed in 0.1.7.

flatpak

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. Prior to version 0.9-rc4, any unprivileged local user can crash avahi-daemon by sending a single D-Bus method call with conflicting publish flags. This issue has been patched in version 0.9-rc4.

avahi

A flaw was found in firewalld. A local unprivileged user can exploit this vulnerability by mis-authorizing two runtime D-Bus (Desktop Bus) setters, setZoneSettings2 and setPolicySettings. This mis-authorization allows the user to modify the runtime firewall state without proper authentication, leading to unauthorized changes in network security configurations.

firewalld · redhat

A flaw was found in systemd. The systemd-machined service contains an Improper Access Control vulnerability due to insufficient validation of the class parameter in the RegisterMachine D-Bus (Desktop Bus) method. A local unprivileged user can exploit this by attempting to register a machine with a specific class value, which may leave behind a usable, attacker-controlled machine object. This allows the attacker to invoke methods on the privileged object, leading to the execution of arbitrary commands with root privileges on the host system.

A flaw was found in the udisks storage management daemon that allows unprivileged users to back up LUKS encryption headers without authorization. The issue occurs because a privileged D-Bus method responsible for exporting encryption metadata does not perform a policy check. As a result, sensitive cryptographic metadata can be read and written to attacker-controlled locations. This weakens the confidentiality guarantees of encrypted storage volumes.

redhat · freedesktop

A flaw was found in the udisks storage management daemon that exposes a privileged D-Bus API for restoring LUKS encryption headers without proper authorization checks. The issue allows a local unprivileged user to instruct the root-owned udisks daemon to overwrite encryption metadata on block devices. This can permanently invalidate encryption keys and render encrypted volumes inaccessible. Successful exploitation results in a denial-of-service condition through irreversible data loss.

redhat · freedesktop

Lack of authorization of the InputManager D-Bus interface in InputPlumber versions before v0.63.0 can lead to local Denial-of-Service, information leak or even privilege escalation in the context of the currently active user session.

Avahi is a system which facilitates service discovery on a local network via the mDNS/DNS-SD protocol suite. In 0.9-rc2 and earlier, an unprivileged local users can crash avahi-daemon (with wide-area disabled) by creating record browsers with the AVAHI_LOOKUP_USE_WIDE_AREA flag set via D-Bus. This can be done by either calling the RecordBrowserNew method directly or creating hostname/address/service resolvers/browsers that create those browsers internally themselves.

avahi

A flaw was found in the Udisks daemon, where it allows unprivileged users to create loop devices using the D-BUS system. This is achieved via the loop device handler, which handles requests sent through the D-BUS interface. As two of the parameters of this handle, it receives the file descriptor list and index specifying the file where the loop device should be backed. The function itself validates the index value to ensure it isn't bigger than the maximum value allowed. However, it fails to validate the lower bound, allowing the index parameter to be a negative value. Under these circumstances, an attacker can cause the UDisks daemon to crash or perform a local privilege escalation by gaining access to files owned by privileged users.

A local privilege escalation vulnerability exists in lastore-daemon, the system package manager daemon used in Deepin Linux (developed by Wuhan Deepin Technology Co., Ltd.). In versions 0.9.53-1 (Deepin 15.5) and 0.9.66-1 (Deepin 15.7), the D-Bus configuration permits any user in the sudo group to invoke the InstallPackage method without password authentication. By default, the first user created on Deepin is in the sudo group. An attacker with shell access can craft a .deb package containing a malicious post-install script and use dbus-send to install it via lastore-daemon, resulting in arbitrary code execution as root.

Zincati is an auto-update agent for Fedora CoreOS hosts. Zincati ships a polkit rule which allows the `zincati` system user to use the actions `org.projectatomic.rpmostree1.deploy` to deploy updates to the system and `org.projectatomic.rpmostree1.finalize-deployment` to reboot the system into the deployed update. Since Zincati v0.0.24, this polkit rule contains a logic error which broadens access of those polkit actions to any unprivileged user rather than just the `zincati` system user. In practice, this means that any unprivileged user with access to the system D-Bus socket is able to deploy older Fedora CoreOS versions (which may have other known vulnerabilities). Note that rpm-ostree enforces that the selected version must be from the same branch the system is currently on so this cannot directly be used to deploy an attacker-controlled update payload. This primarily impacts users running untrusted workloads with access to the system D-Bus socket. Note that in general, untrusted workloads should not be given this access, whether containerized or not. By default, containers do not have access to the system D-Bus socket. The logic error is fixed in Zincati v0.0.30. A workaround is to manually add a following polkit rule, instructions for which are available in the GitHub Security Advisory.

During an annual penetration test conducted on behalf of Axis Communication, Truesec discovered a flaw in the VAPIX Device Configuration framework that could lead to an incorrect user privilege level in the VAPIX service account D-Bus API.

axis

During an annual penetration test conducted on behalf of Axis Communication, Truesec discovered a flaw in the ACAP Application framework that allowed applications to access restricted D-Bus methods within the framework. Axis has released patched AXIS OS versions for the highlighted flaw. Please refer to the Axis security advisory for more information and solution.

axis

An issue was discovered in Deepin dde-api-proxy through 1.0.19 in which unprivileged users can access D-Bus services as root. Specifically, dde-api-proxy runs as root and forwards messages from arbitrary local users to legacy D-Bus methods in the actual D-Bus services, and the actual D-Bus services don't know about the proxy situation (they believe that root is asking them to do things). Consequently several proxied methods, that shouldn't be accessible to non-root users, are accessible to non-root users. In situations where Polkit is involved, the caller would be treated as admin, resulting in a similar escalation of privileges.

A log spoofing flaw was found in the Tuned package due to improper sanitization of some API arguments. This flaw allows an attacker to pass a controlled sequence of characters; newlines can be inserted into the log. Instead of the 'evil' the attacker could mimic a valid TuneD log line and trick the administrator. The quotes '' are usually used in TuneD logs citing raw user input, so there will always be the ' character ending the spoofed input, and the administrator can easily overlook this. This logged string is later used in logging and in the output of utilities, for example, `tuned-adm get_instances` or other third-party programs that use Tuned's D-Bus interface for such operations.

A script injection vulnerability was identified in the Tuned package. The `instance_create()` D-Bus function can be called by locally logged-in users without authentication. This flaw allows a local non-privileged user to execute a D-Bus call with `script_pre` or `script_post` options that permit arbitrary scripts with their absolute paths to be passed. These user or attacker-controlled executable scripts or programs could then be executed by Tuned with root privileges that could allow attackers to local privilege escalation.