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Vapor contains an integer overflow in URI leading to potential host spoofing

Moderate severity GitHub Reviewed Published Jan 3, 2024 in vapor/vapor • Updated Feb 9, 2024

Package

swift github.com/vapor/vapor (Swift)

Affected versions

<= 4.89.3

Patched versions

4.90.0

Description

Vapor's vapor_urlparser_parse function uses uint16_t indexes when parsing a URI's components, which may cause integer overflows when parsing untrusted inputs.

This vulnerability does not affect Vapor directly but could impact applications relying on the URI type for validating user input.

The URI type is used in several places in Vapor. A developer may decide to use URI to represent a URL in their application (especially if that URL is then passed to the HTTP Client) and rely on its public properties and methods. However, URI may fail to properly parse a valid (albeit abnormally long) URL, due to string ranges being converted to 16-bit integers. An attacker may use this behaviour to trick the application into accepting a URL to an untrusted destination.

By padding the port number with zeros, an attacker can cause an integer overflow to occur when the URL authority is parsed and, as a result, spoof the host.

Impact

Users attempting to treat untrusted input as a URI are vulnerable to a host spoofing attack due to an integer overflow.

Workarounds

Validate user input before parsing as a URI or, if possible, use Foundation's URL and URLComponents utilities.

References

@0xTim 0xTim published to vapor/vapor Jan 3, 2024
Published by the National Vulnerability Database Jan 3, 2024
Published to the GitHub Advisory Database Jan 3, 2024
Reviewed Jan 3, 2024
Last updated Feb 9, 2024

Severity

Moderate

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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:L/UI:N/S:U/C:N/I:H/A:N

EPSS score

0.044%
(14th percentile)

CVE ID

CVE-2024-21631

GHSA ID

GHSA-r6r4-5pr8-gjcp

Source code

Credits

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