Fighting persistent malware with a UEFI scanner, or ‘What’s it all about UEFI?”

The short answer to the headline’s question is that a UEFI scanner is all about helping you protect your computer against people who seek to take it over by abusing its Unified Extensible Firmware Interface (UEFI). A successful attack on a system’s UEFI can give the attacker complete control of that system, including persistence: the ability to secretly maintain unauthorized access to the machine despite rebooting and/or reformatting of the hard drive.

As you can imagine, this form of persistence is not a virtue and can prolong the pain and inconvenience of a malicious code infection. If your security software only scan drives and memory, without scanning UEFI, it is possible to think you have a clean machine when you don’t, that’s why we recommend a security solution that scans it, like ESET.

Why does my device have a UEFI?

Computing devices work by executing code: the instructions that we call software and which make the hardware – such as a laptop or smartphone – do something useful. Code can be fed to the device in several ways. For example, it can be read from storage on a disk, held in memory, or delivered via a network connection. But when you power on a digital device it has to start somewhere (bootstrap), and that first piece of code is typically stored in a chip on the device. This code, referred to as firmware, may include a “power-on self-test” or POST to make sure things are working correctly, followed by the loading into memory of the basic instructions for handling input and output.

If you’ve been into computers for a while you might recognize this chip-based code as BIOS or Basic Input Output System. In fact, BIOS technology dates back to the 1970s and so it is not surprising that it would eventually struggle to meet the demands of today’s computers, a point made by my colleague, Cameron Camp, in this excellent article on UEFI scanning. As Cameron details, UEFI technology has evolved to replace BIOS, although some devices still refer to it as BIOS. (I’m tempted to say “Meet the new BIOS, same as the old BIOS” but UEFI is signifcantly different, and besides, this article already has a headline that exploits a classic lyric: “What’s it all about, Alfie?”)


Technically, UEFI is a specification, maintained by the Unified Extensible Firmware Interface Forum ( According to the forum, the specification defines a new model for the interface between personal computer operating systems and platform firmware, and it “consists of data tables that contain platform-related information, plus boot and runtime service calls that are available to the operating system and its boot loader.” Without going into greater technical detail, UEFI added a great deal of functionality to the boot process, including some serious security measures (these are discussed in the  ESET white paper referenced by this article).

Unfortunately, the illicit benefits of devising code that can surreptitiously take over a system early in the boot process – generically referred to as a bootkit – are a powerful motivator to the folks who specialize in unauthorized access to digital devices. Such folks could be: cybercriminals; domestic and foreign agencies like NSA and CIA; and private companies that sell “surveillance tools” to governments.

For more details, check out the excellent article by my ESET colleague Cassius Puodzius that discusses these “threat actors” and their interest in UEFI. The broader topic of bootkit evolution from early days through 2012 is ably covered by ESET Senior Research Fellow, David Harley, in this article. You might also check out the paper “Bootkits, Past, Present, and Future”, presented at Virus Bulletin 2014. And of course there are plenty of technical papers on the UEFI Forum site.

So what’s my UEFI risk?

For most people, this is the right question to be asking, and the right answer will depend on who you are. For example, are you someone whose computer might be of interest to the NSA or CIA or other government entity that has the resources to invest in code that abuses UEFI, either its own code or a commercial surveillance product purchased from a commercial vendor? Are you using your computer to develop, review, or otherwise handle intellectual property worth stealing? If you answered either of those questions in the affirmative, then I would say you have an above average risk of encountering UEFI malware.

Currently, I am not aware of any large-scale, broadly-targeted criminal malware campaigns that exploit UEFI to attack the general public’s computer systems (if you know of any, please share the knowledge). However, even if you are not in a high risk category, I strongly suggest you still need security software with UEFI scanning capability. Why? Remember those three letter agencies that have been developing UEFI attacks? Well, they don’t have a stellar reputation for keeping their tools secret. In fact, the biggest news in malware so far this year has been WannaCryptor a.k.a. WannaCry, and one reason that particular ransomware spread so fast was because it used a “top secret” exploit developed by the NSA, an agency known to have dabbled in UEFI compromise.

In other words, we just don’t know when a new malware campaign that abuses UEFI to maintain persistence on compromised systems will appear in the wild. What I can say is that folks who are performing UEFI scans on a regular basis will be better prepared to protect their systems from future malware than people who are not. And that is what UEFI scanning is all about.

ESET latest endpoint security products now include an industry first UEFI scanning.



About Version 2 Limited

Version 2 Limited is one of the most dynamic IT companies in Asia. The company develops and distributes IT products for Internet and IP-based networks, including communication systems, Internet software, security, network, and media products. Through an extensive network of channels, point of sales, resellers, and partnership companies, Version 2 Limited offers quality products and services which are highly acclaimed in the market. Its customers cover a wide spectrum which include Global 1000 enterprises, regional listed companies, public utilities, Government, a vast number of successful SMEs, and consumers in various Asian cities.


About ESET

Founded in 1992, ESET is a global provider of security software for enterprises and consumers. ESET’s award-winning, antivirus software system, NOD32, provides real-time protection from known and unknown viruses, spyware, rootkits and other malware. ESET NOD32 offers the smallest, fastest and most advanced protection available, with more Virus Bulletin 100 Awards than any other antivirus product. ESET was named to Deloitte’s Technology Fast 500 five years running, and has an extensive partner network, including corporations like Canon, Dell and Microsoft. ESET has offices in Bratislava, SK; Bristol, U.K.; Buenos Aires, AR; Prague, CZ; San Diego, USA; and is represented worldwide in more than 100 countries. 


Cameron Camp,ESET安全研究員


當ESET公司宣布,旗下最新版零售終端防護產品集成了UEFDI掃描功能時,用戶主要反映分為兩種。有些人稱:“太棒了!”;還有人說:“UEFI掃描功能是什麽?”本文就為您提供此問題的答案 – 我想,回答”太棒了!“的人往往是計算機安全領域最新技術的密切關註者,深知這所謂的UEFI往往蘊含著安全隱患。



與計算機系統的其他組件一樣,一旦UEFI被黑客攻擊後,便可獲取系統及其數據的非法訪問權限。UEFI查毒引擎的功能就是檢測和查殺,早於操作系統啟動之前便可執行的一類威脅。此類威脅包括rootkit和勒索病毒在內,針對UEFI之中的安全漏洞發起攻擊,具有很強的頑固性,即使重新安裝操作系統後仍可存活。簡單地說,ESET UEFI查殺引擎的作用就是防範此類攻擊。







青睞於各類新技術的微軟公司也采用了UEFI,從而大大促進了普及度。該公司宣布,從Windows 8起,UEFI成為新型64位計算機的貼標認證要求(原本不支持64位的舊計算機仍可以升級)。畢竟,UEFI提供了一些有趣的安全功能,這是已被淘汰的BIOS所無法實現的。



UEFI平臺初始化啟動流程(Zimmer、Dasari及Brogan 2009年論文第16頁)









如需閱讀We Live Security網站上有關UEFI安全性的更多文章,請訪問以下博客和論文:

·        固件之中植入惡意程序:利用安全假象的攻擊新招 (2017年10月19日)

·        Windows 10安全性及隱私權保護:深入調查和分析 (2016年6月15日)

·        Bookits、Windigo以及Virus Bulletin  (2014年9月30日) 

·        Bootkits:前生、今世和未來 (2014年9月) 

·        Windows 8發布後六個月觀感(白皮書) (2013年6月3日) 

·        白皮書:Windows 8的安全特性(2012年10月9日) 

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ESET成立於1992年,是一家面向企業與個人用戶的全球性的電腦安全軟件提供商,其獲獎產品 — NOD32防病毒軟件系統,能夠針對各種已知或未知病毒、間諜軟件 (spyware)、rootkits和其他惡意軟件為電腦系統提供實時保護。ESET NOD32佔用 系統資源最少,偵測速度最快,可以提供最有效的保護,並且比其他任何防病毒產品獲得了更多的Virus Bulletin 100獎項。ESET連續五年被評為“德勤高科技快速成長500 強”(Deloitte’s Technology Fast 500)公司,擁有廣泛的合作夥伴網絡,包括佳能、戴爾、微軟等國際知名公司,在布拉迪斯拉發(斯洛伐克)、布里斯托爾(英國 )、布宜諾斯艾利斯(阿根廷)、布拉格(捷克)、聖地亞哥(美國)等地均設有辦事處,代理機構覆蓋全球超過100個國家。