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opentelemetry-instrumentation Denial of Service vulnerability due to unbound cardinality metrics

High severity GitHub Reviewed Published Oct 2, 2023 in open-telemetry/opentelemetry-python-contrib • Updated Nov 10, 2023

Package

pip opentelemetry-instrumentation (pip)

Affected versions

< 0.41b0

Patched versions

0.41b0

Description

Summary

Autoinstrumentation out of the box adds the label http_method that has unbound cardinality. It leads to the server's potential memory exhaustion when many malicious requests are sent.

Details

HTTP method for requests can be easily set by an attacker to be random and long.

PoC

Send many requests with long randomly generated HTTP methods and observe how memory consumption increases during it. The app can be like this example from the official docs.

Impact

In order to be affected program has to be instrumented for HTTP handlers and does not filter any unknown HTTP methods on the level of CDN, LB, previous middleware, etc.

Proposed solution

For convenience and safe usage of this library, it should by default mark with the label UNKNOWN non-standard HTTP methods to show that such requests were made (and this way does not increase cardinality). In case someone wants to stay with the current behavior, library API should allow it. The mechanism with environment variables can be reused - introduce the variable OTEL_INSTRUMENTATION_HTTP_CAPTURE_ALL_METHODS that will allow enabling current behavior when someone really wants it.

References

@ocelotl ocelotl published to open-telemetry/opentelemetry-python-contrib Oct 2, 2023
Published to the GitHub Advisory Database Oct 2, 2023
Reviewed Oct 2, 2023
Published by the National Vulnerability Database Oct 6, 2023
Last updated Nov 10, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.104%
(44th percentile)

Weaknesses

CVE ID

CVE-2023-43810

GHSA ID

GHSA-5rv5-6h4r-h22v

Source code

Credits

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