Security Bulletin: Remote Execution Vulnerability Affects Red Hat Linux Used By IBM WebSphere Application Server in IBM Cloud (CVE-2019-12735)

Summary

There is a security vulnerability that affects Red Hat Linux used by IBM WebSphere Application Server in the IBM Cloud.

Vim before 8.1.1365 and Neovim before 0.3.6 allows remote attackers to execute arbitrary OS commands via the :source! command in a modeline, as demonstrated by execute in Vim, and assert_fails or nvim_input in Neovim.

Vulnerability Details

It was found that the :source! command was not restricted by the sandbox mode. If modeline was explicitly enabled, opening a specially crafted text file in vim could result in arbitrary command execution.

Find out more about CVE-2019-12735 from the MITRE CVE dictionary dictionary and NIST NVD.

Relevant CVE Information:

CVEID: CVE-2019-12735 DESCRIPTION: Vim and and Neovim could allow a remote attacker to execute arbitrary commands on the system, caused by improper input validation by the :source! command in a modeline. By sending a specially-crafted request, an attacker could exploit this vulnerability to execute arbitrary commands on the system.
CVSS Base Score: 9.8
CVSS Temporal Score: See <https://exchange.xforce.ibmcloud.com/vulnerabilities/162255&gt; for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

These vulnerabilities affect the following versions and releases of IBM WebSphere Application Server in IBM Cloud:

• Liberty
• Version 9.0
• Version 8.5

Remediation/Fixes

To mitigate the vulnerability on an existing service instance issue the following command as root:

• echo “set nomodeline” >> /etc/vimrc

Alternatively, delete the vulnerable service instance and create a new instance.

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References

Complete CVSS v2 Guide
On-line Calculator v2

Complete CVSS v3 Guide
On-line Calculator v3

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Related Information

IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog

Change History

31 July 2019 - Original document published

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.

Disclaimer

Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.

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