CVE-2020-16929
Microsoft Excel Remote Code Execution Vulnerability
No known exploitation. EPSS puts it in the 89th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
<p>A remote code execution vulnerability exists in Microsoft Excel software when the software fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the current user. If the current user is logged on with administrative user rights, an attacker could take control of the affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. Users whose accounts are configured to have fewer user rights on the system could be less impacted than users who operate with administrative user rights.</p> <p>Exploitation of the vulnerability requires that a user open a specially crafted file with an affected version of Microsoft Excel. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted file to the user and convincing the user to open the file. In a web-based attack scenario, an attacker could host a website (or leverage a compromised website that accepts or hosts user-provided content) containing a specially crafted file designed to exploit the vulnerability. An attacker would have no way to force users to visit the website. Instead, an attacker would have to convince users to click a link, typically by way of an enticement in an email or instant message, and then convince them to open the specially crafted file.</p> <p>The security update addresses the vulnerability by correcting how Microsoft Excel handles objects in memory.</p>
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
3.7% chance of exploitation activity in the next 30 days, which ranks it in the 89th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
7 events over 2078 days, from the signal feeds we watch.
- OpenVAS check added
- EPSS band changemoderate → low
- Patch availablerecord updated
- Publishedweakness classified, att&ck mapped
Affected products
- Microsoft 365 Apps for EnterpriseConsumer Software / productivity
- Microsoft Excel 2010 Service Pack 2Consumer Software / productivity
- excel web appEnterprise Software / document-mgmt
- Microsoft Office 2010 Service Pack 2Consumer Software / productivity
- office online serverEnterprise Software / collaboration-groupware
- office web appsOperating Systems / windows
- sharepoint enterprise serverEnterprise Software / itsm-monitoring
- sharepoint serverEnterprise Software / collaboration-groupware
And 29 more affected products. See all after sign-in
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Scored 7.8 by NVD.
How it is reached
- Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction RequiredA user must click a link, open a file, or perform some action
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- Privilege EscalationT1068Exploitation for Privilege Escalationhigh confidence
Sources
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