Zero-day vulnerability in Serv-U FTP Server

Buffer overflow
CVE-2021-35211

MicrosoftтАЩs research indicates this vulnerability exploit involves a limited, targeted set of customers and a single threat actor.

Vulnerability details

Advisory: SB2021071315 - Remote code execution in SolarWinds Serv-U

Vulnerable component: Serv-U FTP Server

CVE-ID: CVE-2021-35211

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-119 - Memory corruption

Description:

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

The vulnerability exists due to a boundary error. A remote attacker can send a specially crafted request to the Serv-U server, trigger memory corruption and execute arbitrary code on the target system.

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

Note, the vulnerability is being actively exploited in the wild.

External links:

https://www.solarwinds.com/trust-center/security-advisories/cve-2021-35211

About zero-day vulnerabilities

Zero-day vulnerability is an undisclosed vulnerability in software that hackers can exploit to compromise computer programs, gain unauthorized access to sensitive data, penetrate networks, etc. We consider vulnerability a zero-day when there is no solution provided from software vendor and the vulnerability is being actively exploited by malicious actors.

Zero-day candidate is a potential zero-day vulnerability in software which might have been used in targeted attacks, however there is no evidence to support this suggestion.