SB2021020327 - Multiple vulnerabilities in SolarWinds Serv-U FTP Server



SB2021020327 - Multiple vulnerabilities in SolarWinds Serv-U FTP Server

Published: February 3, 2021 Updated: April 17, 2023

Security Bulletin ID SB2021020327
Severity
High
Patch available
YES
Number of vulnerabilities 5
Exploitation vector Remote access
Highest impact Code execution

Breakdown by Severity

High 20% Medium 20% Low 60%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 5 secuirty vulnerabilities.


1) Incorrect default permissions (CVE-ID: CVE-2021-25276)

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to incorrect default permissions on the Windows "Users" directory. A local user with access to the system can view contents of files and obtain users' password hashes from the "%ProgramData%\RhinoSoft\Serv-U\Users\<DOMAIN>\" directory.


2) Cross-site scripting (CVE-ID: CVE-2020-35482)

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


3) Code Injection (CVE-ID: CVE-2020-35481)

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

The vulnerability exists due to improper input validation. A remote attacker can send a specially crafted request and execute arbitrary macros on the target system.

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


4) Path traversal (CVE-ID: CVE-2020-27994)

The vulnerability allows a remote user to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences passed via the "dir" HTTP GET parameter. A remote user can send a specially crafted HTTP request and read arbitrary files on the system.

Example:

https:///[host]/?Command=List&dir=\..\*.*

5) Stored cross-site scripting (CVE-ID: CVE-2020-28001)

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.


Remediation

Install update from vendor's website.