CyberSecBulletin
CVE-2022-31115NVD status: Modified

opensearch-ruby: Deserialization of Untrusted Data

Published Updated By the CyberSecBulletin desk

CVE-2022-31115 is a high-severity deserialization of untrusted data vulnerability in opensearch-ruby from Opensearch-project, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected opensearch-ruby versions: < 2.0.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.62% chance of exploitation within 30 days, higher than 76% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Opensearch to 2.0.2 or a later version.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  4. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Opensearch-projectopensearch-ruby< 2.0.1Not stated
AmazonOpensearchbefore 2.0.22.0.2

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighCNA (github.com)
CVSS 3.18.8HighNVD
CVSS 2.06.8MediumNVD

Official description

opensearch-ruby is a community-driven, open source fork of elasticsearch-ruby. In versions prior to 2.0.1 the ruby `YAML.load` function was used instead of `YAML.safe_load`. As a result opensearch-ruby 2.0.0 and prior can lead to unsafe deserialization using YAML.load if the response is of type YAML. An attacker must be in control of an opensearch server and convince the victim to connect to it in order to exploit this vulnerability. The problem has been patched in opensearch-ruby gem version 2.0.1. Users are advised to upgrade. There are no known workarounds for this issue.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How developers prevent this class of flaw

  • If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Explicitly define a final object() to prevent deserialization.

More Deserialization of Untrusted Data vulnerabilities (CWE-502)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Technical write-ups (may include proof of concept)

Recent Deserialization of Untrusted Data vulnerabilities

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