1) Input validation error

Risk: Medium

CVSSv3: 4.6 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-8162

CWE-ID: CWE-20 - Improper Input Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to insufficient validation of user-supplied input in ActiveStorage's S3 adapter. A remote attacker can control the Content-Length of an S3 direct upload URL without receiving a new signature from the server and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

activestorage: 5.2.0, 5.2.0.beta1, 5.2.0.beta2, 5.2.0.rc1, 5.2.0.rc2, 5.2.1, 5.2.1.1, 5.2.1.rc1, 5.2.2, 5.2.2.1, 5.2.2.rc1, 5.2.3, 5.2.3.rc1, 5.2.4, 5.2.4.1, 5.2.4.2, 5.2.4.rc1, 6.0.0, 6.0.0.beta1, 6.0.0.beta2, 6.0.0.beta3, 6.0.0.rc1, 6.0.0.rc2, 6.0.1, 6.0.1.rc1, 6.0.2, 6.0.2.1, 6.0.2.2, 6.0.2.rc1, 6.0.2.rc2, 6.0.3, 6.0.3.rc1

CPE

• cpe:/a:ruby:activestorage:6.0.3.rc1:
• cpe:/a:ruby:activestorage:6.0.3:
• cpe:/a:ruby:activestorage:6.0.2.rc2:
• cpe:/a:ruby:activestorage:6.0.2.rc1:
• cpe:/a:ruby:activestorage:6.0.2.2:
• cpe:/a:ruby:activestorage:6.0.2.1:
• cpe:/a:ruby:activestorage:6.0.2:
• cpe:/a:ruby:activestorage:6.0.1.rc1:
• cpe:/a:ruby:activestorage:6.0.1:
• cpe:/a:ruby:activestorage:6.0.0.rc2:
• cpe:/a:ruby:activestorage:6.0.0.rc1:
• cpe:/a:ruby:activestorage:6.0.0.beta3:
• cpe:/a:ruby:activestorage:6.0.0.beta2:
• cpe:/a:ruby:activestorage:6.0.0.beta1:
• cpe:/a:ruby:activestorage:6.0.0:
• cpe:/a:ruby:activestorage:5.2.4.rc1:
• cpe:/a:ruby:activestorage:5.2.4.2:
• cpe:/a:ruby:activestorage:5.2.4.1:
• cpe:/a:ruby:activestorage:5.2.4:
• cpe:/a:ruby:activestorage:5.2.3.rc1:
• cpe:/a:ruby:activestorage:5.2.3:
• cpe:/a:ruby:activestorage:5.2.2.rc1:
• cpe:/a:ruby:activestorage:5.2.2.1:
• cpe:/a:ruby:activestorage:5.2.2:
• cpe:/a:ruby:activestorage:5.2.1.rc1:
• cpe:/a:ruby:activestorage:5.2.1.1:
• cpe:/a:ruby:activestorage:5.2.1:
• cpe:/a:ruby:activestorage:5.2.0.rc2:
• cpe:/a:ruby:activestorage:5.2.0.rc1:
• cpe:/a:ruby:activestorage:5.2.0.beta2:
• cpe:/a:ruby:activestorage:5.2.0.beta1:
• cpe:/a:ruby:activestorage:5.2.0:

External links

https://snyk.io/vuln/SNYK-RUBY-ACTIVESTORAGE-569602
https://github.com/rails/rails/commit/c0ab9a7d29b84a6ccb1ffa3e8ca1ce61f7a9fbb8
https://groups.google.com/forum/#!topic/rubyonrails-security/PjU3946mreQ
https://hackerone.com/reports/789579

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.