Two features appear on the typical email security datasheet, usually as a pair of words in a feature table: sandboxing and CDR. Both are about attachments, both are in the package we sell, and both are worth understanding before you buy, because your Microsoft 365 or Google Workspace plan may already include a version of one of them. This post explains what each does in the vendor's own words, what the difference is, what the suites include at which plan level, and who needs the dedicated version. It stays on attachments; links and impersonation are their own posts.
In short: a sandbox opens an attachment in an isolated virtual machine and watches what it does, to catch malware that signature scanning has not seen before. CDR (content disarm and reconstruction) does not try to judge the file; it removes the parts that can carry code, such as macros and embedded objects, and delivers a clean copy, with the original available on request. One detects, the other removes. Microsoft lists Business Premium as including its sandbox (Safe Attachments); Business Basic and Standard are not on its list and need the add-on. Google Workspace Business Standard and above include a sandbox; Business Starter is not on Google's list.
Neither suite's built-in tier includes CDR as Check Point defines it. If your business receives invoices, contracts, resumes or spreadsheets from outside, the pair is worth having; if it mostly sends, the suite's own sandbox may be enough.
What a sandbox does
Antivirus scanning matches a file against known malware. A sandbox handles the file that has not been seen before. Check Point's administration guide describes its Anti-Malware engine this way: "It uses Check Point to detect files containing known malware (Anti-Virus) and Check Point's advanced sandbox (Threat Emulation) to detect the evasive zero-day malware." The mechanism, in the same guide: "During sandboxing, the Check Point Anti-Malware (Check Point SandBlast) (Threat Emulation) engine opens the file in a secured virtual machine and baits it to trigger its malicious behavior." And the reason it matters: "Sandboxing attachments and shared files is crucial for detecting advanced zero-day unknown malware hidden in them." One practical limit from the guide: the engine "inspects files attached to an email or shared via supported file sharing/messaging applications for malware only if it is less than 50 MB." A sandbox is a detection control. It gives a verdict, and the verdict can be wrong in either direction, which is why the second feature exists.
What CDR does
CDR takes a different position: it does not need to decide whether the file is malicious, because it removes the parts that could be. Check Point calls its implementation Attachment Cleaning, and defines it as "a Content Disarm and Reconstruction (CDR) engine that serves as an additional layer of security for email attachments on top of the Anti-Malware engine." The order of operations is explicit: "After the Anti-Malware security engine determines an attachment is not malicious, Attachment Cleaning (Threat Extraction) delivers a secure version of the attachment to the end user, removing hyperlinks behind text, macros, and other active content that may contain malware."
There are two modes. "Clean - removes macros, embedded objects, and any active content from the attachment while maintaining the file type." "Convert - the file is converted into PDF format, regardless of its original file type, ensuring no active content can ever be a part of it." Check Point notes that "While the Convert option is considered to be secure, it has an impact on user experience and productivity," and recommends Clean unless strict regulatory or organizational policy requirements say otherwise. The supported file types are the ones that carry active content in an office: PDF, and the Word, Excel and PowerPoint families (DOCX, DOCM, DOC, XLSX, XLSM, XLS, PPTX, PPTM, PPT, plus their template, add-in and binary variants).
What the recipient sees: "By default, the cleaned file will have threat_extracted_ mentioned before the file name." If the person needs the original, "Click the link below the attachment in the email," and "If prompted, enter the reason for restoring the attachment, and click Submit." The administrator chooses the policy from three options: "User is allowed to request a restore for any attachment (admin must approve)," "User is allowed to restore benign attachments only," or "User is allowed to restore any attachment." Check Point adds that where approval is not required, "the original email is delivered to the user immediately," and "This action does not require the help desk's intervention." For a ten-person company, the middle option is usually right: a spreadsheet the sandbox judged clean can be restored by the person who needs the macros, and a file it judged malicious is not one the user can restore under that option.
Why the two go together
A sandbox answers "is this file bad?" CDR answers "does this file need to carry code?" For the invoice, the contract and the resume, the answer to the second question is no, so the macros and embedded objects can go regardless of what the sandbox thought. The combination means an unknown sample that fools the sandbox still arrives with its macros and embedded objects removed, for the file types on the list, and a legitimate macro-enabled workbook from your accountant is one click away from being restored. Check Point's own framing is that Attachment Cleaning sits "on top of the Anti-Malware engine," not instead of it. Two limits apply to the pair as to anyone's: a sandbox adds time before delivery, and cleaning covers only the listed file types, so a file outside that list, an archive for example, passes through uncleaned and relies on the other engines.
What Microsoft 365 and Google Workspace already include
Microsoft's sandbox is Safe Attachments. From Microsoft Learn: "Safe Attachments in Microsoft Defender for Office 365 provides an additional layer of protection for email attachments that have already been scanned by Anti-malware protection," and "Specifically, Safe Attachments uses a virtual environment to check attachments in email messages for harmful attachments (for example, malware, ransomware, and phishing) before they're delivered to recipients (a process known as detonation)." It has a delivery option called Dynamic Delivery, which "Delivers messages immediately, but replaces attachments with placeholders until Safe Attachments scanning is complete." Which plans have it: Microsoft's service description states "Defender for Office 365 Plan 1: Included in Microsoft 365 Business Premium and, effective July 1, 2026, in Office 365 E3 and Microsoft 365 E3." Business Basic and Business Standard are not on that list; Microsoft's plan options page says standalone services "can also be added to Business and Enterprise service family plans that don't already include them," which is the add-on route.
Google's sandbox is called Security Sandbox: "It works by scanning incoming email attachments in a secure, isolated environment called a Security Sandbox to identify malware in the attachments without risking any harm to your organization." Google lists the editions: "Supported editions for this feature: Frontline Plus; Business Standard and Business Plus; Enterprise Standard and Enterprise Plus." Business Starter is not listed. On timing, Google says "While scanning does add a slight delay, the scan should be complete within a few minutes." Separately, Google's attachment protection settings cover three cases in plain words: "Protect against attackers who use encrypted attachments, which can't be scanned for malware"; "Protect against documents that contain malicious scripts that can harm your devices"; and "Protect against attachment file types that are uncommon for your domain," because "Uncommon and archaic file types can be used to spread malware." These three are settings, not a sandbox, and they are worth turning on where your edition shows them.
One more built-in control sits on the desktop rather than in the mailbox. Microsoft changed Office's default on Windows so that macros in files from the internet are blocked: "VBA macros are a common way for malicious actors to gain access to deploy malware and ransomware," and "Therefore, to help improve security in Office, we're changing the default behavior of Office applications to block macros in files from the internet." That default is a safety net for the macro case specifically; it does not cover embedded objects, scripts in PDFs, or a user who unblocks the file.
Neither suite's built-in tier describes a CDR function as Check Point defines it, delivering a cleaned copy with the original on request. That is the part a dedicated layer adds.
Where the pair sits in Check Point's packages
Check Point's licensing page describes the Advanced Protect package as one that "Includes phishing protection, account takeover protection, and protection against known and unknown malicious URLs (URL Emulation) as well as known and unknown malicious files (Sandbox and CDR)." Complete Protect "Includes Advanced Protect plus Data Loss Prevention (DLP)." On Check Point's plans page, the rows "Complete known malware and zero-day malware prevention (Sandboxing)" and "Attachment sanitization (CDR; Threat Extraction)" are marked included in each of the four packages. Our Managed Email Security runs on Advanced Protect, Email Only, so both features are in the package rather than add-ons; the license-only route carries whichever package matches your quote. The same package also replaces links for inspection at click time: "Click-Time Protection replaces links in the email's body and attachments," so that "every time a user clicks on a link, the website behind the link is inspected to ensure it is not a phishing website." Links are a separate post; the point here is that the attachment features arrive with the URL features, not separately.
Do you need them?
The honest test is what arrives, not what you send. Check Point Research's figure, published April 2025: "While 68% of malicious attacks are delivered through email, PDF-based attacks now account for 22% of all malicious email attachments, according to Check Point Research." PDF is the format businesses accept from strangers, which is why the number matters more than the headline. If your inbox receives invoices from suppliers, contracts from counterparties, resumes from applicants, or spreadsheets from clients, you are receiving exactly the file types on Check Point's Attachment Cleaning list from people you cannot vet, and the pair is worth having. If your mail is mostly internal or outbound, the suite's sandbox, where your plan includes it, plus the three Google settings or the Microsoft presets, covers the common case.
Three checks before deciding. First, find your plan: Microsoft 365 Business Premium or Google Business Standard and above means a sandbox is already included; Business Basic, Business Standard on Microsoft, or Google Business Starter means it is not. Second, confirm the built-in sandbox is actually on: Google's Security Sandbox is off by default and needs an admin to enable it; Microsoft's Built-in protection preset applies Safe Attachments to recipients not covered by another Safe Attachments policy. Third, ask who in the company opens attachments from people they have not met: accounts payable, HR, sales. Those mailboxes are where CDR earns its place.
How to start
Managed Email Security is the Check Point Advanced Protect license (sandbox, CDR, click-time protection, anti-phishing and account takeover protection) plus our managed service: business-day quarantine review, release requests, investigation, a monthly summary and 24/7 support, with a one-time SaaS security posture report of your Microsoft 365 or Google Workspace tenant within the first 90 days at no charge. It is $6.40 per user per month on the year-end offer ($5.60 for registered 501(c)(3) nonprofits; $8 list). The offer is 20% off (30% for registered 501(c)(3) nonprofits) on a 12-month Managed Email Security agreement signed by December 31, 2026, new customers only, no onboarding fee. If you already have an IT provider and only want the license, the license-only route explains how we beat a written quote, like for like.
Either way, the free two-week email security assessment runs in Monitor only and reports the sandbox verdicts and the attachments of the file types Attachment Cleaning covers, for the attachments that actually reached you. We work with small and medium businesses and nonprofits nationwide, including Washington DC, Northern Virginia, and Maryland. Book a free 15-minute call or see the services page.
Sources: Check Point Harmony Email & Collaboration administration guide, Anti-Malware (Check Point SandBlast, Threat Emulation); Attachment Cleaning (Threat Extraction) overview, supported file types, end-user experience and workflows; Click-Time Protection overview; Licensing the Email Security product (pages dated 2026-07-29); Check Point, Harmony Email & Collaboration plans and packages page (2026-09-24); Check Point Research, "The Weaponization of PDFs" (April 2, 2025); Microsoft Learn, Safe Attachments in Microsoft Defender for Office 365 (updated 2026-08-10); Microsoft Defender for Office 365 service description (updated 2026-07-17); Microsoft 365 plan options (2025-07-18); Microsoft Learn, Macros from the internet are blocked by default in Office (updated 2026-07-17); Google Workspace Admin Help, Security Sandbox overview and Advanced phishing and malware protection (updated 2026-10-20). Quotes are verbatim from those pages as read on October 21, 2026.
