CyberSecBulletin
CVE-2024-27918NVD status: Analyzed

Coder allows oragnizations to provision remote development environments via Terraform.

Published Updated By the CyberSecBulletin desk

CVE-2024-27918 is a high-severity improper input validation vulnerability in coder, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 2.6.1, 2.7.3, 2.8.4 as the first without the flaw, so updating coder to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.97% chance of exploitation within 30 days, higher than 62% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update coder to 2.6.1 or 2.7.3 or 2.8.4, whichever matches your release line, 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.

Affected products and versions

VendorProductAffected versionsFixed in
Codercoder>= 2.8.0, < 2.8.4; >= 2.7.0, < 2.7.3; < 2.6.1; before 2.6.1; 2.7.0 up to, but not including, 2.7.3; 2.8.0 up to, but not including, 2.8.42.6.1, 2.7.3, 2.8.4

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
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
LowSome restricted data can be read.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H. Scored by CNA (github.com).

Official description

Coder allows oragnizations to provision remote development environments via Terraform. Prior to versions 2.6.1, 2.7.3, and 2.8.4, a vulnerability in Coder's OIDC authentication could allow an attacker to bypass the `CODER_OIDC_EMAIL_DOMAIN` verification and create an account with an email not in the allowlist. Deployments are only affected if the OIDC provider allows users to create accounts on the provider. During OIDC registration, the user's email was improperly validated against the allowed `CODER_OIDC_EMAIL_DOMAIN`s. This could allow a user with a domain that only partially matched an allowed domain to successfully login or register. An attacker could register a domain name that exploited this vulnerability and register on a Coder instance with a public OIDC provider. Coder instances with OIDC enabled and protected by the `CODER_OIDC_EMAIL_DOMAIN` configuration are affected. Coder instances using a private OIDC provider are not affected, as arbitrary users cannot register through a private OIDC provider without first having an account on the provider. Public OIDC providers are impacted. GitHub authentication and external authentication are not impacted. This vulnerability is remedied in versions 2.8.4, 2.7.3, and 2.6.1 All versions prior to these patches are affected by the vulnerability.*It is recommended that customers upgrade their deployments as soon as possible if they are utilizing OIDC authentication with the `CODER_OIDC_EMAIL_DOMAIN` setting.

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

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in coder

All coder vulnerabilities

Recent Improper Input Validation vulnerabilities

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