CVE-2016-4437 Apache Shiro: login or permission bypass
In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.
Confirmed exploited by CISA on · US federal patch deadline May 3, 2022
What to do
- Install Apache's security update for Shiro. 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
- Apache Shiro Code Execution Vulnerability
- Product
- Apache Shiro
- CISA description
- Apache Shiro contains a vulnerability which may allow remote attackers to execute code or bypass intended access restrictions via an unspecified request parameter when a cipher key has not been configured for the "remember me" feature.
- Type of flaw
- Login or permission bypass (CWE-284)
- Confirmed exploited
- Nov 3, 2021
- US federal patch deadline
- May 3, 2022
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Answering about CVE-2016-4437 ·
Questions about CVE-2016-4437
Is CVE-2016-4437 being exploited?
Yes. CISA added CVE-2016-4437 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2016-4437?
Install Apache's security update for Shiro. 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-2016-4437?
Only if you use Apache Shiro. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.