Security updates released for Adobe Reader zero-day vulnerability to arbitrary code execution

Adobe is warning customers of a critical zero-day bug that is active in the wild affecting its Adobe Acrobat PDF reader software.

The bug, tracked as CVE-2021-28550, affects eight versions of Adobe software (full list below) and exploits vulnerabilities in the software including arbitrary code execution, memory leaks and exposure of private information.

10 critical and four important vulnerabilities were addressed in Adobe Reader and Acrobat in addition to five critical flaws in Adobe Illustrator that were resolved by Tuesday’s security patch release. The technical specific details of the bug were not available to Adobe software users until after the 43 patch fixes were downloaded which meant that before manual user installation, the zero-day bug allowed for hackers to execute virtually any command on targeted systems.

Users can download these new security fixes by initiating the auto update feature of Acrobat and Reader by going to Help –> Check for Updates and installing via the Adobe Download Centre. This will remove the user intervention necessity to manually install security updates and allows Adobe products to update automatically upon detection of patch releases.

List of affected Adobe software versions:

– Acrobat DC, 2021.001.20150  and earlier versions - Windows

– Acrobat Reader DC, 2021.001.20150  and earlier versions – Windows

– Acrobat DC, 2021.001.20149  and earlier versions - macOS

– Acrobat Reader DC, 2021.001.20149  and earlier versions – macOS

– Acrobat 2020, 2020.001.30020 and earlier versions – Windows & macOS

– Acrobat Reader 2020, 2020.001.30020 and earlier versions – Windows & macOS

– Acrobat 2017, 2017.011.30194  and earlier versions – Windows & macOS

– Acrobat Reader 2017, 2017.011.30194  and earlier versions – Windows & macOS


Zepto Cryptolocker Alert: Lineal intercepts dangerous zero-day threat with ESET Antivirus

Zepto

Yesterday Lineal’s team successfully rescued a client from a new ‘zero-day’ Cryptolocker Virus which nearly destroyed many of their files.

The dangerous variation of the ‘Zepto’ cryptolocker, only identified online during the last 24 hours, is believed to be a brand new threat originally derived from ‘Locky’ ransomware.

An employee at one of Lineal’s IT support clients recently opened an email containing an infected file – a malicious piece of obfuscated code written in Visual Basic scripting language. The installed Zepto cryptolocker began encrypting the company’s files, readying to demand a heavy ransom.

In a coordinated attack, an outside user also forced access to our client’s server, instructing it to begin sending fake Barclays ‘phishing’ emails, attempting to criminally capture banking details.

Our team caught both threats early, forcefully locking out the intruder in mid-session, identifying the employee who introduced the threat, and quarantining the infection with ESET’s business endpoint security. 

Lineal then notified ESET about Zepto to help with future identification, having avoided the need to restore all the clients files from backup at great disruption.

The landscape of online security threats is rapidly changing, and Cryptolocker variants have spread quickly in recent months.

In this case Lineal’s rapidly responding team and professional security software helped our client dodge the huge potential losses from the security breach – and highlighted how vital it is that organisations of all sizes take proactive steps to protect their IT from hostile intrusion.

 

For IT security advice and support, contact Lineal today.