Vulnerabilities > CVE-2018-15442 - OS Command Injection vulnerability in Cisco Webex Meetings Desktop and Webex Productivity Tools
Attack vector
LOCAL Attack complexity
LOW Privileges required
LOW Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
A vulnerability in the update service of Cisco Webex Meetings Desktop App for Windows could allow an authenticated, local attacker to execute arbitrary commands as a privileged user. The vulnerability is due to insufficient validation of user-supplied parameters. An attacker could exploit this vulnerability by invoking the update service command with a crafted argument. An exploit could allow the attacker to run arbitrary commands with SYSTEM user privileges. While the CVSS Attack Vector metric denotes the requirement for an attacker to have local access, administrators should be aware that in Active Directory deployments, the vulnerability could be exploited remotely by leveraging the operating system remote management tools.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 5 |
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Command Line Execution through SQL Injection An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
- Command Delimiters An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or a blacklist input validation, as opposed to whitelist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or blacklist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
- Exploiting Multiple Input Interpretation Layers An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
- Argument Injection An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
- OS Command Injection In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.
Exploit-Db
file exploits/windows/local/45696.rb id EDB-ID:45696 last seen 2018-11-30 modified 2018-10-25 platform windows port published 2018-10-25 reporter Exploit-DB source https://www.exploit-db.com/download/45696 title WebEx - Local Service Permissions Exploit (Metasploit) type local file exploits/windows/remote/45695.rb id EDB-ID:45695 last seen 2018-11-30 modified 2018-10-25 platform windows port published 2018-10-25 reporter Exploit-DB source https://www.exploit-db.com/download/45695 title WebExec - Authenticated User Code Execution (Metasploit) type remote
Metasploit
description This module enables the execution of a single command as System by exploiting a remote code execution vulnerability in Cisco's WebEx client software. id MSF:AUXILIARY/ADMIN/SMB/WEBEXEC_COMMAND last seen 2020-01-01 modified 2018-10-24 published 2018-10-23 references reporter Rapid7 source https://github.com/rapid7/metasploit-framework/blob/master//modules/auxiliary/admin/smb/webexec_command.rb title WebEx Remote Command Execution Utility description This module uses a valid username and password of any level (or password hash) to execute an arbitrary payload. This module is similar to the "psexec" module, except allows any non-guest account by default. id MSF:EXPLOIT/WINDOWS/SMB/WEBEXEC last seen 2020-06-14 modified 2018-10-24 published 2018-10-23 references reporter Rapid7 source https://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/windows/smb/webexec.rb title WebExec Authenticated User Code Execution description This module exploits a flaw in the 'webexservice' Windows service, which runs as SYSTEM, can be used to run arbitrary commands locally, and can be started by limited users in default installations. id MSF:EXPLOIT/WINDOWS/LOCAL/WEBEXEC last seen 2020-06-07 modified 2020-05-08 published 2018-10-23 references reporter Rapid7 source https://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/windows/local/webexec.rb title WebEx Local Service Permissions Exploit
Nessus
| NASL family | CGI abuses |
| NASL id | CISCO_WEBEX_MEETINGS_WIN_33_6_4.NASL |
| description | The version of Cisco Webex Desktop App installed on the remote host is prior to 33.6.4, and thus, is affected by a command injection vulnerability. |
| last seen | 2020-05-15 |
| modified | 2018-12-27 |
| plugin id | 119888 |
| published | 2018-12-27 |
| reporter | This script is Copyright (C) 2018-2020 and is owned by Tenable, Inc. or an Affiliate thereof. |
| source | https://www.tenable.com/plugins/nessus/119888 |
| title | Cisco Webex Meetings Desktop App < 33.6.4 Command Injection Vulnerability |
| code | |
Packetstorm
data source https://packetstormsecurity.com/files/download/149946/windows-smb-webexec.rb.txt id PACKETSTORM:149946 last seen 2018-10-25 published 2018-10-24 reporter Ron source https://packetstormsecurity.com/files/149946/WebExec-Authenticated-User-Code-Execution.html title WebExec Authenticated User Code Execution data source https://packetstormsecurity.com/files/download/150495/CORE-2018-0011.txt id PACKETSTORM:150495 last seen 2018-11-29 published 2018-11-28 reporter Core Security Technologies source https://packetstormsecurity.com/files/150495/Cisco-WebEx-Meetings-Privilege-Escalation.html title Cisco WebEx Meetings Privilege Escalation data source https://packetstormsecurity.com/files/download/149945/windows-local-webexec.rb.txt id PACKETSTORM:149945 last seen 2018-10-25 published 2018-10-24 reporter Jeff McJunkin source https://packetstormsecurity.com/files/149945/WebEx-Local-Service-Permissions-Code-Execution.html title WebEx Local Service Permissions Code Execution