CVE-2020-0796 Microsoft SMBv3: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Aug 10, 2022
What to do
- Install Microsoft's security update for SMBv3. 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.
- Patch anything in this catalog first, ahead of normal patch cycles.
- 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
- Microsoft SMBv3 Remote Code Execution Vulnerability
- Product
- Microsoft SMBv3
- CISA description
- A remote code execution vulnerability exists in the way that the Microsoft Server Message Block 3.1.1 (SMBv3) protocol handles certain requests. An attacker who successfully exploited the vulnerability could gain the ability to execute code on the target server or client.
- Type of flaw
- Memory-safety flaw (CWE-119)
- Confirmed exploited
- Feb 10, 2022 — known to be used in ransomware attacks
- US federal patch deadline
- Aug 10, 2022
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Answering about CVE-2020-0796 ·
Questions about CVE-2020-0796
Is CVE-2020-0796 being exploited?
Yes. CISA added CVE-2020-0796 to its Known Exploited Vulnerabilities catalog on Feb 10, 2022, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2020-0796?
Install Microsoft's security update for SMBv3. 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-2020-0796?
Only if you use Microsoft SMBv3. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.