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Privilege escalation on xrdp-sesman

High
metalefty published GHSA-8h98-h426-xf32 Feb 7, 2022

Package

xrdp (none)

Affected versions

0.9.18, 0.9.17

Patched versions

>= 0.9.18.1

Description

Reported by Gilad Kleinman.

An integer underflow leading to a heap overflow in the sesman server allows any unauthenticated attacker which is accessible to a sesman server (listens by default on localhost when installing xrdp, but can be remote if configured otherwise) to execute code as root.

Impact

Root code execution on any sesman server accessible.

Patches

Patched in versions 0.9.18.1 or 0.9.19 and above

Workarounds

None

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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2022-23613

Weaknesses

Improper Handling of Length Parameter Inconsistency

The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data. Learn more on MITRE.

Integer Underflow (Wrap or Wraparound)

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. Learn more on MITRE.

Numeric Range Comparison Without Minimum Check

The product checks a value to ensure that it is less than or equal to a maximum, but it does not also verify that the value is greater than or equal to the minimum. Learn more on MITRE.

Credits