Actively exploited vulnerability
Microsoft Office: memory corruption flaw under attack
CVE-2015-1770 · Microsoft Office Uninitialized Memory Use Vulnerability
What is affected
Microsoft Office is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.
Microsoft Office allows remote attackers to execute arbitrary code via a crafted Office document.
What an attacker can do
This is a memory corruption flaw. It lets an attacker corrupt the program's memory by feeding it specially crafted content: a web page, a file or a network message. The result ranges from a crash to the attacker running their own code.
- How it is reached
- Over the internet or network
- Access the attacker needs
- No account needed
- Does the victim have to do something?
- Yes, the victim must open or click something
What to do
- Update Microsoft Office now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
- Turn on automatic updates so the next fix arrives without you having to look for it.
- If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.
Apply updates per vendor instructions.
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on March 28, 2022, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by April 18, 2022, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 35% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 98% of all scored vulnerabilities.
Its CVSS severity score is 8.8 out of 10 (high), as recorded in the US National Vulnerability Database.
Technical description
Microsoft Office 2013 SP1 and 2013 RT SP1 allows remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Uninitialized Memory Use Vulnerability."