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  3. CVE-2021-35247
Exploited in the wildServers & business softwareWork IT

CVE-2021-35247 SolarWinds Serv-U: software flaw

In plain words: A mistake in the software that attackers have found a way to abuse. Depends on the product — see the description and the vendor advisory.

Confirmed exploited by CISA on · US federal patch deadline Feb 4, 2022

What to do

  1. Install SolarWinds's security update for Serv-U. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Keep a list of every internet-facing server you run so nothing is forgotten.
  3. Patch anything in this catalog first, ahead of normal patch cycles.
  4. Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.

The details

Official name
SolarWinds Serv-U Improper Input Validation Vulnerability
Product
SolarWinds Serv-U
CISA description
SolarWinds Serv-U versions 15.2.5 and earlier contain an improper input validation vulnerability that allows attackers to build and send queries without sanitization.
Type of flaw
Software flaw (CWE-20)
Confirmed exploited
Jan 21, 2022
US federal patch deadline
Feb 4, 2022

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Answering about CVE-2021-35247 ·

Questions about CVE-2021-35247

Is CVE-2021-35247 being exploited?

Yes. CISA added CVE-2021-35247 to its Known Exploited Vulnerabilities catalog on Jan 21, 2022, which means there is reliable evidence of real-world attacks.

How do I fix CVE-2021-35247?

Install SolarWinds's security update for Serv-U. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.

Am I affected by CVE-2021-35247?

Only if you use SolarWinds Serv-U. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

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