Vulnerability identifier: #VU31144

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-9897

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PuTTY
Client/Desktop applications / Software for system administration

Vendor: Simon Tatham

Description

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

Multiple denial-of-service attacks that can be triggered by writing to the terminal exist in PuTTY versions before 0.71.

Mitigation
Install update from vendor's website.

Vulnerable software versions

PuTTY: 0.45 - 0.70

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External links
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00004.html
http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00020.html
http://lists.debian.org/debian-lts-announce/2019/04/msg00023.html
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/36LWQ3NPFIV7DC7TC4KFPRYRH2OR7SZ2/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LDO3F267P347E6U2IILFCYW7JPTLCCES/
http://seclists.org/bugtraq/2019/Apr/6
http://security.netapp.com/advisory/ntap-20190404-0001/
http://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html
http://www.debian.org/security/2019/dsa-4423

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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.