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Merged
terrancedejesus merged 19 commits into from
Dec 5, 2025
Merged

[New Rule] React2Shell Detection #5408

terrancedejesus merged 19 commits into from
Dec 5, 2025
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@terrancedejesus terrancedejesus commented Dec 4, 2025 •
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Fixes #5406

Pull Request

Issue link(s):

Summary - What I changed

Adds a BBR rule for Potential React.JS CVE-2025-55182 Exploit Attempt. Please see issue for more details. Testing has been done locally and on a deployed Azure instance with a custom app.

Screenshot 2025-12-04 at 1 54 19 PM

How To Test

Query can be used in TRADE stack for verifying logic, reviewing events captured, etc.

Checklist

  • Added a label for the type of pr: bug, enhancement, schema, maintenance, Rule: New, Rule: Deprecation, Rule: Tuning, Hunt: New, or Hunt: Tuning so guidelines can be generated
  • Added the meta:rapid-merge label if planning to merge within 24 hours
  • Secret and sensitive material has been managed correctly
  • Automated testing was updated or added to match the most common scenarios
  • Documentation and comments were added for features that require explanation

Contributor checklist

@terrancedejesus terrancedejesus added the Rule: New Proposal for new rule label Dec 4, 2025
@terrancedejesus terrancedejesus self-assigned this Dec 4, 2025
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github-actions bot commented Dec 4, 2025

Rule: New - Guidelines

These guidelines serve as a reminder set of considerations when proposing a new rule.

Documentation and Context

  • Detailed description of the rule.
  • List any new fields required in ECS/data sources.
  • Link related issues or PRs.
  • Include references.

Rule Metadata Checks

  • creation_date matches the date of creation PR initially merged.
  • min_stack_version should support the widest stack versions.
  • name and description should be descriptive and not include typos.
  • query should be inclusive, not overly exclusive, considering performance for diverse environments. Non ecs fields should be added to non-ecs-schema.json if not available in an integration.
  • min_stack_comments and min_stack_version should be included if the rule is only compatible starting from a specific stack version.
  • index pattern should be neither too specific nor too vague, ensuring it accurately matches the relevant data stream (e.g., use logs-endpoint.process-* for process data).
  • integration should align with the index. If the integration is newly introduced, ensure the manifest, schemas, and new_rule.yaml template are updated.
  • setup should include the necessary steps to configure the integration.
  • note should include any additional information (e.g. Triage and analysis investigation guides, timeline templates).
  • tags should be relevant to the threat and align/added to the EXPECTED_RULE_TAGS in the definitions.py file.
  • threat, techniques, and subtechniques should map to ATT&CK always if possible.

New BBR Rules

  • building_block_type should be included if the rule is a building block and the rule should be located in the rules_building_block folder.
  • bypass_bbr_timing should be included if adding custom lookback timing to the rule.

Testing and Validation

  • Provide evidence of testing and detecting the expected threat.
  • Check for existence of coverage to prevent duplication.

Samirbous
Samirbous approved these changes Dec 4, 2025
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@terrancedejesus terrancedejesus marked this pull request as ready for review December 4, 2025 19:09
@terrancedejesus terrancedejesus changed the title [New Rule] BBR - Potential React.JS CVE-2025-55182 Exploit Attempt [New Rule] BBR - Potential React CVE-2025-55182 Exploit Attempt Dec 4, 2025
@botelastic botelastic bot added the bbr Building Block Rules label Dec 4, 2025
Mikaayenson
Mikaayenson reviewed Dec 4, 2025
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@Mikaayenson Mikaayenson left a comment •
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Do RSC frameworks have unique features that could help this detection as-is? We can probably expand this beyond just nextjs flight behavior.

Based on traditional react apps and the event loop, I'd expect we would also want to capture the promise in this detection. Effectively that's the core of this cve.

Samirbous
Samirbous approved these changes Dec 4, 2025
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tradebot-elastic commented Dec 5, 2025 •
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⛔️ Test failed

Results
  • ❌ Potential React Server Components RCE Attempt (CVE-2025-55182) (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

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tradebot-elastic commented Dec 5, 2025 •
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@terrancedejesus terrancedejesus changed the title [New Rule] BBR - Potential React CVE-2025-55182 Exploit Attempt [New Rule] React2Shell Detection Dec 5, 2025
@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

eric-forte-elastic
eric-forte-elastic reviewed Dec 5, 2025
View reviewed changes
rules/network/initial_access_react_server_components_rce_attempt.toml Outdated
(
http.request.body.content like~ "*__proto__*" or
http.request.body.content like~ "*prototype*"
) and http.request.body.content like~ "*constructor*")
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@eric-forte-elastic eric-forte-elastic Dec 5, 2025 •
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Just double checking, should this be an and here or should we be using constructor as a filter? It looks like the exploit does not need to use the Function constructor. Clearly some do, and this appears to be the proper way to exploit the vulnerability (ref). However, if there is an RSC Flight implementation that does expose other functions might we miss it this way? (ref)

^ granted I know the earlier query phrase will catch the exploitation itself regardless so might not be worth the effort/potential noise. Generally speaking, __proto__ or prototype on their own are indicative of malicious behavior in Flight. (ref)

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@terrancedejesus terrancedejesus Dec 5, 2025

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@eric-forte-elastic great point! If I understand you correctly, the constructor is just one of many potential gadgets that could be used where __proto__ and prototype are nefarious enough in an RSC flight chunk?

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
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tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@tradebot-elastic
Copy link

tradebot-elastic commented Dec 5, 2025 •
edited
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⛔️ Test failed

Results
  • ❌ React2Shell (CVE-2025-55182) Exploitation Attempt (eql)
    • coverage_issue: no_rta
    • stack_validation_failed: no_rta

@terrancedejesus terrancedejesus merged commit 0b94991 into main Dec 5, 2025
13 checks passed
@terrancedejesus terrancedejesus deleted the terrancedejesus/issue5406 branch December 5, 2025 23:37
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@eric-forte-elastic eric-forte-elastic eric-forte-elastic left review comments

@Mikaayenson Mikaayenson Mikaayenson approved these changes

@imays11 imays11 imays11 approved these changes

@Samirbous Samirbous Samirbous approved these changes

@w0rk3r w0rk3r Awaiting requested review from w0rk3r

@DefSecSentinel DefSecSentinel Awaiting requested review from DefSecSentinel

@Aegrah Aegrah Awaiting requested review from Aegrah

@shashank-elastic shashank-elastic Awaiting requested review from shashank-elastic

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[New Rule] BBR - Potential React.JS CVE-2025-55182 Exploit Attempt

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