Local Privilege Escalation via Race Condition in TeamViewer Patch Management for Windows

A race condition in the installation process of TeamViewer Remote Management - Patch Management for Windows prior to version 26.9.1 allows a local authenticated attacker with low privileges to execute arbitrary code with elevated privileges by replacing the service executable in an insufficiently protected temporary directory during Patch Management activation.

Improper Access Control in TeamViewer clients

Improper access control in the TeamViewer Full and Host clients (Windows, macOS, Linux) prior version 15.74.5 allows an authenticated user to bypass additional access controls with “Allow after confirmation” configuration in a remote session. An exploit could result in unauthorized access prior to local confirmation. The user needs to be authenticated for the remote session via ID/password, Session Link, or Easy Access as a prerequisite to exploit this vulnerability.

Privilege Escalation via Symbolic Link Spoofing in TeamViewer Client

Improper handling of symbolic links in the TeamViewer Full Client and Host for Windows — in versions prior to 15.70 of TeamViewer Remote and Tensor — allows an attacker with local, unprivileged access to a device lacking adequate malware protection to escalate privileges by spoofing the update file path. This may result in unauthorized access to sensitive information.

TeamViewer Desktop through 14.7.1965 allows a bypass of remote-login access control because the same key is used for different customers' installations. It used a shared AES key for all installations since at least as far back as v7.0.43148, and used it for at least OptionsPasswordAES in the current version of the product. If an attacker were to know this key, they could decrypt protect information stored in the registry or configuration files of TeamViewer. With versions before v9.x , this allowed for attackers to decrypt the Unattended Access password to the system (which allows for remote login to the system as well as headless file browsing). The latest version still uses the same key for OptionPasswordAES but appears to have changed how the Unattended Access password is stored. While in most cases an attacker requires an existing session on a system, if the registry/configuration keys were stored off of the machine (such as in a file share or online), an attacker could then decrypt the required password to login to the system.

Untrusted search path vulnerability in TeamViewer 5.0.8703 and earlier allows local users, and possibly remote attackers, to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse dwmapi.dll that is located in the same folder as a .tvs or .tvc file.

TeamViewer Linux - Deletion command not properly executed after process crash

TeamViewer Linux versions before 15.28 do not properly execute a deletion command for the connection password in case of a process crash. Knowledge of the crash event and the TeamViewer ID as well as either possession of the pre-crash connection password or local authenticated access to the machine would have allowed to establish a remote connection by reusing the not properly deleted connection password.

This vulnerability allows local attackers to disclose sensitive information on affected installations of TeamViewer. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the TeamViewer service. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated array. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-13818.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of TeamViewer 15.16.8.0. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of TVS files. The issue results from the lack of proper validation of user-supplied data, which can result in a memory corruption condition. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-13697.

This vulnerability allows remote attackers to execute arbitrary code on affected installations of TeamViewer. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of TVS files. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated structure. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-13606.

TeamViewer before 14.7.48644 on Windows loads untrusted DLLs in certain situations.

TeamViewer Desktop for Windows before 15.8.3 does not properly quote its custom URI handlers. A malicious website could launch TeamViewer with arbitrary parameters, as demonstrated by a teamviewer10: --play URL. An attacker could force a victim to send an NTLM authentication request and either relay the request or capture the hash for offline password cracking. This affects teamviewer10, teamviewer8, teamviewerapi, tvchat1, tvcontrol1, tvfiletransfer1, tvjoinv8, tvpresent1, tvsendfile1, tvsqcustomer1, tvsqsupport1, tvvideocall1, and tvvpn1. The issue is fixed in 8.0.258861, 9.0.258860, 10.0.258873, 11.0.258870, 12.0.258869, 13.2.36220, 14.2.56676, 14.7.48350, and 15.8.3.

An issue was discovered in the Chat functionality of the TeamViewer desktop application 14.3.4730 on Windows. (The vendor states that it was later fixed.) Upon login, every communication is saved within Windows main memory. When a user logs out or deletes conversation history (but does not exit the application), this data is not wiped from main memory, and therefore could be read by a local user with the same or greater privileges.

In Omron CX-Supervisor, Versions 3.5 (12) and prior, Omron CX-Supervisor ships with Teamviewer Version 5.0.8703 QS. This version of Teamviewer is vulnerable to an obsolete function vulnerability requiring user interaction to exploit.

A DLL side loading vulnerability in the Windows Service in TeamViewer versions up to 11.0.133222 (fixed in 11.0.214397), 12.0.181268 (fixed in 12.0.214399), 13.2.36215 (fixed in 13.2.36216), and 14.6.4835 (fixed in 14.7.1965) on Windows could allow an attacker to perform code execution on a target system via a service restart where the DLL was previously installed with administrative privileges. Exploitation requires that an attacker be able to create a new file in the TeamViewer application directory; directory permissions restrict that by default.

An issue was discovered in TeamViewer 14.2.2558. Updating the product as a non-administrative user requires entering administrative credentials into the GUI. Subsequently, these credentials are processed in Teamviewer.exe, which allows any application running in the same non-administrative user context to intercept them in cleartext within process memory. By using this technique, a local attacker is able to obtain administrative credentials in order to elevate privileges. This vulnerability can be exploited by injecting code into Teamviewer.exe which intercepts calls to GetWindowTextW and logs the processed credentials.

TeamViewer 10.x through 13.x allows remote attackers to bypass the brute-force authentication protection mechanism by skipping the "Cancel" step, which makes it easier to determine the correct value of the default 4-digit PIN.

TeamViewer through 13.1.1548 stores a password in Unicode format within TeamViewer.exe process memory between "[00 88] and "[00 00 00]" delimiters, which might make it easier for attackers to obtain sensitive information by leveraging an unattended workstation on which TeamViewer has disconnected but remains running.

Improper access control in the clipboard synchronization feature

Improper access control in the clipboard synchronization feature in TeamViewer Full Client prior version 15.57 and TeamViewer Meeting prior version 15.55.3 can lead to unintentional sharing of the clipboard with the current presenter of a meeting.