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MEDIUM

CVE-2020-5217

CVE-2020-5217 — Directive injection when using dynamic overrides with user input in RubyGems secure_headers

In Secure Headers (RubyGem secure_headers), a directive injection vulnerability is present in versions before 3.8.0, 5.1.0, and 6.2.0. If user-supplied input was passed into append/override_content_security_policy_directives, a semicolon could be injected leading to directive injection. This could be used to e.g. override a script-src directive. Duplicate directives are ignored and the first one wins. The directives in secure_headers are sorted alphabetically so they pretty much all come before script-src. A previously undefined directive would receive a value even if SecureHeaders::OPT_OUT was supplied. The fixed versions will silently convert the semicolons to spaces and emit a deprecation warning when this happens. This will result in innocuous browser console messages if being exploited/accidentally used. In future releases, we will raise application errors resulting in 500s.…

Published Updated Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

2%

chance of exploitation in 30 days

Affects

twitter

secure_headers

CVSS base

4.4

MEDIUM

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

twitter

Products (1)

secure headers

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
4.4CVSS 3.1MEDIUM——cvelistV5

Weakness & attack patterns

  • CWE-95

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1027.006Obfuscated Files or Information: HTML Smuggling
  • T1027.009Obfuscated Files or Information: Embedded Payloads
  • T1564.009Hide Artifacts: Resource Forking

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /override_content_security_policy_directives, /accidentally.

References

4 on the record

Elsewhere on this site

  • twitterevery CVE for this vendor
  • CWE-95other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.