External risk intelligence

Microsoft Office Remote Code Execution Vulnerability.

CVE advisoryKnown Exploit

CVE-2021-27059

Microsoft Office has a remote code execution vulnerability. This could allow an attacker to run malicious code on an affected system, potentially leading to unauthorized system control and data compromise. This vulnerability poses a business risk.

1Halo Surface Signal

Remote Code Execution

Microsoft Office

201020132016

External exposure likelihood

Halo Surface Signal score for CVE-2021-27059

This vulnerability affects Microsoft Office, which is client-side productivity software. It requires a user to open a malicious file locally and is not an internet-facing service, appliance, or gateway that listens for unsolicited network connections.

Horizon Alert

Summary of the vulnerability and why it matters

Microsoft Office contains a remote code execution vulnerability. This flaw could allow an attacker to run arbitrary code on a targeted system. The potential impact involves unauthorized system control and data compromise.

  • Microsoft Office software
  • Unspecified flaw allowing code execution
  • Unauthorized system control and data compromise

Attack Path

How an attacker could exploit the issue

This vulnerability allows an attacker to execute code remotely on a targeted organization's system. An attacker could gain initial access through a specially crafted document that, when opened by a user, triggers the vulnerability. This could lead to the attacker gaining control over certain aspects of the affected system, impacting confidentiality, integrity, and availability of data and applications.

  • Network exposure required
  • Attacker accesses via malicious document
  • Trigger results in code execution

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in Microsoft Office could allow attackers to execute code remotely. Exploitation would likely require a user to interact with a specially crafted document, and the attacker would need to have authenticated access to the target system. The potential impact includes significant compromise of confidential data and disruption of business operations. Organizations should prioritize addressing this issue.

  • High attacker skill level required.
  • Requires authenticated access and user interaction.
  • Significant business risk and urgency.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Microsoft Office presents a high risk due to its potential for remote code execution, impacting confidentiality, integrity, and availability. Organizations should prioritize addressing this to mitigate business risk.

  • Find affected Microsoft Office assets.
  • Reduce exposure or isolate risk.
  • Apply vendor fixes and verify.
  • Monitor for related activity.

Frequently asked questions

What is Microsoft Office and its role in CVE-2021-27059?

Microsoft Office is a suite of productivity software applications. CVE-2021-27059 is a remote code execution vulnerability that affects specific versions of Microsoft Office, allowing an attacker to run arbitrary code on a targeted system.

What type of weakness does CVE-2021-27059 represent?

CVE-2021-27059 represents a remote code execution (RCE) vulnerability. This means an attacker can execute their own code on a user's computer by exploiting this flaw in Microsoft Office.

How can CVE-2021-27059 be triggered?

This vulnerability can be triggered when a user opens a specially crafted Microsoft Office document. Attack vectors include email attachments, malicious web downloads, or files shared through collaboration platforms.

Why is CVE-2021-27059 considered relevant according to Halo Surface Signal?

Halo Surface Signal assesses this vulnerability as 'very unlikely' to be exploited via internet-facing services because it affects client-side productivity software and requires local user interaction with a malicious file.

What are the recommended actions to address CVE-2021-27059?

Organizations should apply Microsoft security updates for affected Office versions immediately. Additional protective measures include enabling Protected View, blocking macros from the internet, implementing application whitelisting, and educating users about safe document handling practices.

References