Vulnerability identifier: #VU52349

Vulnerability risk: High

CVSSv3.1: 7.8 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-26561

CWE-ID: CWE-121

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
DiskStation Manager (DSM)
Server applications / File servers (FTP/HTTP)

Vendor: Synology Inc.

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing "syno_finder_site" HTTP header. A remote unauthenticated attacker can perform a man-in-the-middle attack, trigger stack-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

DiskStation Manager (DSM): 6.2.3 25426-2

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External links
http://www.synology.com/security/advisory/Synology_SA_20_26
http://www.talosintelligence.com/vulnerability_reports/TALOS-2020-1159

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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.