CVE-2020-8165: A deserialization of untrusted data vulnernerability exists in rails < 5.2.4.3, rails < 6.0.3.1 that can allow an attacker to unmarshal user

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• debian debian linux10.0
• debian debian linux8.0
• debian debian linux9.0
• opensuse leap15.1
• opensuse leap15.2
• rubyonrails railsbefore 5.2.4.3
• rubyonrails rails6.0.0 and later · before 6.0.3.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.

• n/a https://github.com/rails/rails

  • Fixed in 5.2.4.3, 6.0.3.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2019-5418There is a File Content Disclosure vulnerability in Action View <5.2.2.1, <5.1.6.2, <5.0.7.2, <4.2.11.1 and v3 where specially crafted accepKEV
  90Now
• CVE-2016-0752Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, anKEV
  89Now
• CVE-2019-5420A remote code execution vulnerability in development mode Rails <5.2.2.1, <6.0.0.beta3 can allow an attacker to guess the automatically gene
  66This week

Published before and after this one in the same product

• ← EarlierCVE-2020-8162Jun 19, 2020 · A client side enforcement of server side security vulnerability exists in rails < 5.2.4.2 and rails < 6.0.3.1 ActiveStorage's S3 adapter tha
  31Monitor
• ← EarlierCVE-2020-8164Jun 19, 2020 · A deserialization of untrusted data vulnerability exists in rails < 5.2.4.3, rails < 6.0.3.1 which can allow an attacker to supply informati
  31Monitor
• Later →CVE-2020-8167Jun 19, 2020 · A CSRF vulnerability exists in rails <= 6.0.3 rails-ujs module that could allow attackers to send CSRF tokens to wrong domains.
  26Monitor

Root cause

Data received over the network is deserialized into the language’s native object format without verifying its source. Code paths inside the object can be triggered during deserialization.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1payload = sock.recv(65536)2job = pickle.loads(payload)

1payload = sock.recv(65536)2if not hmac.compare_digest(sign(payload), header_sig):3    raise PermissionError("invalid signature")4job = JobSchema.validate(json.loads(payload))

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.