Vulnerability record · CVE-2019-18988 · published 7 February 2020
CVE-2019-18988: TeamViewer Desktop shared AES key bypasses remote-login access control
Teamviewer · Teamviewer
TeamViewer Desktop through 14.7.1965 uses the same AES key across all customer installations, including for OptionsPasswordAES. Anyone who knows that key can decrypt protected values in the registry or configuration files, and on versions before v9.x this exposed the Unattended Access password used for remote login.
Description
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.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Automated analysis
high priorityThe flaw allows credential decryption and remote login, has a public exploit, and is in CISA KEV, though it generally requires local access or off-host configuration exposure.
What it is
TeamViewer Desktop through 14.7.1965 uses the same AES key across all customer installations, including for OptionsPasswordAES. Anyone who knows that key can decrypt protected values in the registry or configuration files, and on versions before v9.x this exposed the Unattended Access password used for remote login.
Impact
An attacker who obtains the shared key and access to the stored configuration can recover credentials and gain remote login to the system, including headless file browsing on older versions.
Attack surface
The CVSS vector is local (AV:L) with low privileges (PR:L) and no user interaction, so in most cases an attacker needs an existing session on the host. The description notes that if registry or configuration keys are stored off the machine, such as on a file share or online, the attacker can decrypt the password without a local session.
Exploitation
CVE-2019-18988 is listed in CISA KEV with a due date of 2022-05-03, and a public exploit reference is present, so exploitation is known. EPSS 30-day probability is 0.04707 (91st percentile), and no ransomware campaign use is documented.
What to do
- Apply the vendor update per TeamViewer's advisory for CVE-2019-18988; do not rely on the shared key remaining secret.
- Rotate the Unattended Access password and any other credentials protected by OptionsPasswordAES after patching.
- Restrict access to registry and configuration stores, and remove TeamViewer configuration files from file shares or online storage.
- Limit local interactive sessions and privileges on hosts running affected TeamViewer Desktop versions.
Detection
- Monitor for access to TeamViewer registry keys and configuration files, especially from unexpected processes or users.
- Alert on TeamViewer remote-login or unattended-access sessions that originate from unusual accounts or hosts.
- Hunt for known public exploit artifacts or tooling associated with CVE-2019-18988 on endpoints.
- Audit hosts for TeamViewer Desktop versions at or below 14.7.1965 and track remediation.
This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.
Exploitation in the wild
CISA added CVE-2019-18988 to the Known Exploited Vulnerabilities catalog on 3 November 2021 as "TeamViewer Desktop Bypass Remote Login Vulnerability". Required action: Apply updates per vendor instructions. Federal deadline 3 May 2022.
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://community.teamviewer.com/t5/Announcements/Specification-on-CVE-2019-18988/td-p/82264 | Vendor Advisory |
| https://community.teamviewer.com/t5/Knowledge-Base/tkb-p/Knowledgebase?threadtype=label&labels=Security | Broken LinkVendor Advisory |
| https://twitter.com/Blurbdust/status/1224212682594770946?s=20 | Third Party Advisory |
| https://whynotsecurity.com/blog/teamviewer/ | ExploitThird Party Advisory |
| https://community.teamviewer.com/t5/Announcements/Specification-on-CVE-2019-18988/td-p/82264 | Vendor Advisory |
| https://community.teamviewer.com/t5/Knowledge-Base/tkb-p/Knowledgebase?threadtype=label&labels=Security | Broken LinkVendor Advisory |
| https://twitter.com/Blurbdust/status/1224212682594770946?s=20 | Third Party Advisory |
| https://whynotsecurity.com/blog/teamviewer/ | ExploitThird Party Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-18988 | US Government Resource |
Track CVE-2019-18988 inside VULONE
Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.
Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2019-18988), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
