sudo up to 1.8.27 Runas Restriction input validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.3$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in sudo up to 1.8.27. The affected element is an unknown function of the component Runas Restriction Handler. Such manipulation with the input -1/4294967295 leads to input validation. This vulnerability is listed as CVE-2019-14287. The attack may be performed from remote. In addition, an exploit is available. This vulnerability is historically impactful due to its background and the reception it garnered. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in sudo up to 1.8.27 (Operating System Utility Software). It has been rated as critical. Affected by this issue is an unknown part of the component Runas Restriction Handler. The manipulation with the input value -1/4294967295 leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In Sudo before 1.8.28, an attacker with access to a Runas ALL sudoer account can bypass certain policy blacklists and session PAM modules, and can cause incorrect logging, by invoking sudo with a crafted user ID. For example, this allows bypass of !root configuration, and USER= logging, for a "sudo -u \#$((0xffffffff))" command.

The weakness was presented 10/14/2019 by Joe Vennix with Apple as minus_1_uid.html as confirmed advisory (Website). The advisory is shared for download at sudo.ws. The public release was coordinated in cooperation with the vendor. This vulnerability is handled as CVE-2019-14287. The attack may be launched remotely. A simple authentication is necessary for exploitation. Technical details as well as a public exploit are known. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/16/2025). This vulnerability has a historic impact due to its background and reception. The advisory points out:

When sudo is configured to allow a user to run commands as an arbitrary user via the ALL keyword in a Runas specification, it is possible to run commands as root by specifying the user ID -1 or 4294967295. This can be used by a user with sufficient sudo privileges to run commands as root even if the Runas specification explicitly disallows root access as long as the ALL keyword is listed first in the Runas specification. Log entries for commands run this way will list the target user as 4294967295 instead of root. In addition, PAM session modules will not be run for the command.

A public exploit has been developed by Joe Vennix and been published immediately after the advisory. The exploit is available at sudo.ws. It is declared as proof-of-concept. As 0-day the estimated underground price was around $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 236710 (Alibaba Cloud Linux 3 : 0113: sudo (ALINUX3-SA-2022:0113)), which helps to determine the existence of the flaw in a target environment. The code used by the exploit is:

sudo -u#-1 id -u
The advisory illustrates:
Exploiting the bug requires that the user have sudo privileges that allow them to run commands with an arbitrary user ID. Typically, this means that the user's sudoers entry has the special value ALL in the Runas specifier.

Upgrading to version 1.8.28 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (47502) and Tenable (236710). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 7.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 8.8
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Joe Vennix
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 236710
Nessus Name: Alibaba Cloud Linux 3 : 0113: sudo (ALINUX3-SA-2022:0113)

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Upgrade: sudo 1.8.28

Timelineinfo

07/27/2019 🔍
10/14/2019 +79 days 🔍
10/14/2019 +0 days 🔍
10/14/2019 +0 days 🔍
10/15/2019 +1 days 🔍
05/16/2025 +2040 days 🔍

Sourcesinfo

Advisory: minus_1_uid.html
Researcher: Joe Vennix
Organization: Apple
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2019-14287 (🔍)
GCVE (CVE): GCVE-0-2019-14287
GCVE (VulDB): GCVE-100-143468
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 10/15/2019 09:28
Updated: 05/16/2025 20:27
Changes: 10/15/2019 09:28 (56), 10/15/2019 09:33 (18), 01/08/2024 14:40 (4), 12/28/2024 05:17 (15), 05/16/2025 20:27 (2)
Complete: 🔍
Submitter: misc
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #100: sudo: Potential bypass of Runas user restrictions (by misc)

Once again VulDB remains the best source for vulnerability data.

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