#VU29374 Allocation of Resources Without Limits or Throttling in LibVNCServer - CVE-2020-14405

Vulnerability identifier: #VU29374

Vulnerability risk: Medium

CVSSv4.0: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-14405

CWE-ID: CWE-770

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
LibVNCServer
Server applications / Remote management servers, RDP, SSH

Vendor: LibVNC

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists in libvncclient/rfbproto.c due to LibVNCServer does not limit TextChat size.A remote attacker who controls a malicious VNC server can send large amounts of data to the client application and perform a denial of service (DoS) attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

LibVNCServer: 0.9.0 - 0.9.12

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External links
https://github.com/LibVNC/libvncserver/commit/8937203441ee241c4ace85da687b7d6633a12365
https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.