Moderate
CVE-2020-17091
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Description
URL
Type
CVE-2020-17091
MITRE ATT&CK
Collection
Command and Control
Credential Access
Defense Evasion
Discovery
Execution
Exfiltration
Impact
Initial Access
Lateral Movement
Persistence
Privilege Escalation
Description
Microsoft Teams Remote Code Execution Vulnerability
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Ratings
-
Attacker ValueMedium
-
ExploitabilityVery Low
Technical Analysis
Reasoning for low attacker value:
The web app is always up to date. The desktop client updates itself automatically. Teams checks for updates every few hours behind the scenes, downloads it, and then waits for the computer to be idle before silently installing the update, more info here
There is no supported way to prevent updates, more info here
The vulnerability itself is pretty bad, provided the attacker has local access to teams they can trigger RCE by a novel XSS injection in teams.microsoft.com that requires zero user interaction. However because Microsoft has made it quite difficult for users to stay on a vulnerable version, this makes it quite difficult for an attacker to get value out of the vulnerability. More info here
It also should be noted that the RCE gets triggered by the XSS injection that has to be sent through teams.microsoft.com – it is possible, though untested, that Microsoft has already patched this server side – not allowing the known XSS trigger to be pasted through to affected clients
It’s recommended you double check Microsoft Teams is up to date and auto updates are working as expected.
CVSS V3 Severity and Metrics
General Information
Vendors
- Microsoft
Products
- Microsoft Teams
References
Additional Info
Technical Analysis
Report as Exploited in the Wild
What do we mean by "exploited in the wild"?
By selecting this, you are verifying to the AttackerKB community that either you, or a reputable source (example: a security vendor or researcher), has observed an active attempt by attackers, or IOCs related, to exploit this vulnerability outside of a research environment.
A vulnerability should also be considered "exploited in the wild" if there is a publicly available PoC or exploit (example: in an exploitation framework like Metasploit).
