For each ASF setting, the following options are available in anti-spam policies: On: ASF adds the corresponding X-header field to the message, and either marks the message as Spam (SCL 5 or 6 for Increase spam score settings) or High confidence spam (SCL 9 for Mark as spam settings). You can only have one SPF TXT record for a domain. Sender Policy Framework (SPF) allows email administrators to reduce sender-address forgery (spoofing) by specifying which are allowed to send email for a domain. These are added to the SPF TXT record as "include" statements. The SPF -all mechanism denotes SPF hardfail (emails that fail SPF will not be delivered) for emails that do not pass SPF check and is the recommended . Messages that contain numeric-based URLs (typically, IP addresses) are marked as spam. However, if you bought Office 365 Germany, part of Microsoft Cloud Germany, you should use the include statement from line 4 instead of line 2. SPF, together with DKIM and DMARC helps to prevent spoofing of your mail domain. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. In the next two articles (Implementing SPF Fail policy using Exchange Online rule (dealing with Spoof E-mail attack) | Phase 1 learning mode | Part 2#3 and Implementing SPF Fail policy using Exchange Online rule (dealing with Spoof E-mail attack) | Phase 2 production | part 3#3), we will review in details the implementation of SPF fail policy by using an Exchange Online rule. You can identify messages that were filtered by ASF by: The following sections describe the ASF settings and options that are available in anti-spam policies in the Microsoft 365 Defender portal, and in Exchange Online PowerShell or standalone EOP PowerShell (New-HostedContentFilterPolicy and Set-HostedContentFilterPolicy). Misconception 3: In Office 365 and Exchange Online based environment the SPF protection mechanism is automatically activated. The following examples show how SPF works in different situations. SPF is the first line of defense in this and is required by Microsoft when you want to use a custom domain instead of the onmicrosoft.com domain. If you have a custom domain or are using on-premises Exchange servers along with Microsoft 365, you need to manually set up DMARC for your outbound mail. Even when we get to the production phase, its recommended to choose a less aggressive response. The most important purpose of the learning/inspection mode phase is to help us to locate cracks and grooves in our mail infrastructure. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); LazyAdmin.nl is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. The enforcement rule is usually one of these options: Hard fail. If the receiving server finds out that the message comes from a server other than the Office 365 messaging servers listed in the SPF record, the receiving mail server can choose to reject the message as spam. Use the 90-day Defender for Office 365 trial at the Microsoft 365 Defender portal trials hub. This scenario can have two main clarifications: A legitimate technical problem a scene in which we are familiar with the particular mail server/software component, that sent an email message on behalf of our domain, A non-legitimate mail element a scenario in which we discover that our organization uses mail server or mail applications that send an E-mail message on behalf of our domain, and we are now aware of these elements.. You can read a detailed explanation of how SPF works here. SPF is added as a TXT record that is used by DNS to identify which mail servers can send mail on behalf of your custom domain. The E-mail is a legitimate E-mail message. Can we say that we should automatically block E-mail message which their organization doesnt support the use of SPF? To get started, see Use DKIM to validate outbound email sent from your custom domain in Microsoft 365. By analyzing the information thats collected, we can achieve the following objectives: 1. When it finds an SPF record, it scans the list of authorized addresses for the record. This phase is described as learning mode or inspection mode because the purpose of this step has been just to identify an event of a Spoof mail attack in which the hostile element uses an E-mail address that includes our domain name + Log this information. The SPF information identifies authorized outbound email servers. To work around this problem, use SPF with other email authentication methods such as DKIM and DMARC. For questions and answers about anti-malware protection, see Anti-malware protection FAQ. If you have anti-spoofing enabled and the SPF record: hard fail (MarkAsSpamSpfRecordHardFail) turned on, you will probably get more false positives. Fix Your SPF Errors Now SPF Check Path The path for the check is as follows Exchange Admin Center > Protection > Spam Filter > Double Click Default > Advanced Options > Set SPF record: Hard fail: Off One of the prime reasons why Office 365 produces a validation error is an invalid SPF record. One drawback of SPF is that it doesn't work when an email has been forwarded. We reviewed the need for completing the missing part of our SPF implementation, in which we need to capture an event of SPF sender verification test in which the result is fail and, especially, in a scenario in which the sender E-mail address includes our domain name (most likely certainly a sign that this is a Spoof mail attack). In the current article series, our primary focus will be how to implement an SPF policy for incoming mail, by using the option of Exchange rule, and not by using the Exchange Online spam filter policy option. v=spf1 ip4:10.10.10.1/16 mx ptr:Sender.domain.com include:spf.protection.outlook.com ~all. The second one reads the "Authentication-Results" line in the header information and if it says "Fail" sends the email to quarantine. Depending on the property, ASF detections will either mark the message as Spam or High confidence spam. What does SPF email authentication actually do? Find out more about the Microsoft MVP Award Program. The reason could be a problem with the SPF record syntax, a specific mail flow, such as E-mail forwarding that leads to this result, and so on. This is no longer required. 0 Likes Reply Scenario 1. Even in a scenario in which the mail infrastructure of the other side support SPF, in case that the SPF verification test marked as Fail, we cannot be sure that the spoofed E-mail will be blocked. This tag allows plug-ins or applications to run in an HTML window. You intend to set up DKIM and DMARC (recommended). A5: The information is stored in the E-mail header. For example: Previously, you had to add a different SPF TXT record to your custom domain if you were using SharePoint Online. Given that we are familiar with the exact structure of our mail infrastructure, and given that we are sure that our SPF record includes the right information about our mail servers IP address, the conclusion is that there is a high chance that the E-mail is indeed spoofed E-mail! First, we are going to check the expected SPF record in the Microsoft 365 Admin center. I hate spam to, so you can unsubscribe at any time. In simple words, the destination recipient is not aware of a scenario in which the SPF result is Fail, and they are not aware of the fact that the E-mail message could be a spoofed E-mail. Microsoft itself first adopted the new email authentication requirements several weeks before deploying it to customers. SPF works best when the path from sender to receiver is direct, for example: When woodgrovebank.com receives the message, if IP address #1 is in the SPF TXT record for contoso.com, the message passes the SPF check and is authenticated. The presence of filtered messages in quarantine. Each include statement represents an additional DNS lookup. ip6 indicates that you're using IP version 6 addresses. I always try to make my reviews, articles and how-to's, unbiased, complete and based on my own expierence. You add an SPF TXT record that lists the Office 365 messaging servers as legitimate mail servers for your domain. For example, at the time of this writing, Salesforce.com contains 5 include statements in its record: To avoid the error, you can implement a policy where anyone sending bulk email, for example, has to use a subdomain specifically for this purpose. The decision regarding the question, how to relate to a scenario in which the SPF results define as None and Fail is not so simple. The SPF mechanism doesnt perform and concrete action by himself. Continue at Step 7 if you already have an SPF record. This option enables us to activate an EOP filter, which will mark incoming E-mail message that has the value of "SFP =Fail" as spam mail (by setting a high SCL value). The main purpose of SPF is to serve as a solution for two main scenarios: A Spoof mail attacks scenario, in which hostile element abuses our organizational identity, by sending a spoofed E-mail message to external recipients, using our organizational identity (our domain name). One of the options that can be activated is an option named SPF record: hard fail. By default, this option is not activated. However, anti-phishing protection works much better to detect these other types of phishing methods. Now that Enhanced Filtering for Connectors is available, we no longer recommended turning off anti-spoofing protection when your email is routed through another service before EOP. When this mechanism is evaluated, any IP address will cause SPF to return a fail result. Phishing emails Fail SPF but Arrive in Inbox Posted by enyr0py 2019-04-23T19:01:42Z. Identify a possible miss configuration of our mail infrastructure. Some services have other, more strict checks, but few go as far as EOP to block unauthenticated email and treat them as spoofed messages. In this phase, we will need to decide what is the concrete action that will apply for a specific E-mail message that will identify a Spoof mail (SPF = Fail). @tsulaI solved the problem by creating two Transport Rules. Microsoft maintains a dynamic but non-editable list of words that are associated with potentially offensive messages. Solved Microsoft Office 365 Email Anti-Spam. Instead, the E-mail message will be forwarded to a designated authority, such as IT person, that will get the suspicious E-mail, and this person will need to carefully examine the E-mail and decide if the E-mail is indeed spoofed E-mail or a legitimate E-mail message that mistakenly identified as Spoof mail. Also, if your custom domain does not have an SPF TXT record, some receiving servers may reject the message outright. Another distinct advantage of using Exchange Online is the part which enables us to select a very specific response (action), that will suit our needs such as Perpend the E-mail message subject, Send warning E-mail, send the Spoof mail to quarantine, generate the incident report and so on. Misconception 1: Using SPF will protect our organization from every scenario in which hostile element abuses our organizational identity. . If you don't use a custom URL (and the URL used for Office 365 ends in onmicrosoft.com), SPF has already been set up for you in the Office 365 service. In addition to IP addresses, you can also configure your SPF TXT record to include domains as senders. For information about the domains you'll need to include for Microsoft 365, see External DNS records required for SPF. For example, in an Exchange Online based environment, we can activate an Exchange Online server setting that will mark each E-mail message that didnt pass the SPF verification test (SPF = fail) as spam mail. Think of your scanners that send email to external contacts, (web)applications, newsletters systems, etc. In Office 365 based environment (Exchange Online and EOP) beside the option of using Exchange rule, we can use an additional option the spam filter policy. Use the syntax information in this article to form the SPF TXT record for your custom domain. Oct 26th, 2018 at 10:51 AM. When you have created a new Office 365 tenant and your subscription includes Exchange Online or Teams, then you will need to add a couple of DNS records. Include the following domain name: spf.protection.outlook.com. On-premises email organizations where you route. This type of scenario, there is a high chance that we are experiencing a Spoof mail attack! SPF identifies which mail servers are allowed to send mail on your behalf. SPF discourages cybercriminals from spoofing your domain, spam filters will be less likely to blacklist it. Add SPF Record As Recommended By Microsoft. In each of the above scenarios, the event in which the SPF sender verification test ended with SPF = Fail result is not good. As of October 2018, spoof intelligence is available to all organizations with mailboxes in Exchange Online, and standalone EOP organizations without Exchange Online mailboxes. For a list of domain names you should include for Microsoft 365, see External DNS records required for SPF. Anti-spoofing protection considers both SPF hard fails and a much wider set of criteria. For example, exacttarget.com has created a subdomain that you need to use for your SPF TXT record: When you include third-party domains in your SPF TXT record, you need to confirm with the third-party which domain or subdomain to use in order to avoid running into the 10 lookup limit. This is the default value, and we recommend that you don't change it. Mark the message with 'hard fail' in the message envelope and then follow the receiving server's configured spam policy for this type of message. A3: To improve the ability of our mail infrastructure, to recognize the event in which there is a high chance, that the sender spoofs his identity or a scenario in which we cannot verify the sender identity.The other purpose of the SPF is to protect our domain mane reputation by enabling another organization to verify the identity of an E-mail message that was sent by our legitimate users. As mentioned, in an Exchange-based environment, we can use the Exchange rule as a tool that will help us to capture the event of SPF = Fail and also, choose the required response to such an event. Messages sent from an IP address that isn't specified in the SPF Sender Policy Framework (SPF) record in DNS for the source email domain are marked as high confidence spam. Hope this helps. Also, if you're using DMARC with p=quarantine or p=reject, then you can use ~all. Most of the mail infrastructures will leave this responsibility to us meaning the mail server administrator. SPF validates the origin of email messages by verifying the IP address of the sender against the alleged owner of the sending domain. Add a predefined warning message, to the E-mail message subject. This type of mail threat appears in two flavors: In this section, I would like to review a couple of popular misconceptions that relate to the SPF standard. If you have a hybrid environment with Office 365 and Exchange on-premises. The -all rule is recommended. For example, vs. the Exchange Online spam filter policy that marks every incoming E-mail message that has the value of SPF = Fail as spam mail without distinction, when using the option of Exchange rule, we can define a more refined version of this scenario, a condition in which only if the sender uses our domain name + the result from the SPF verification test is Fail, only, then the E-mail message will be identified as Spoof mail. It's a first step in setting up the full recommended email authentication methods of SPF, DKIM, and DMARC. All SPF TXT records end with this value. This tag allows the embedding of different kinds of documents in an HTML document (for example, sounds, videos, or pictures). An SPF record is a list of authorized sending hosts for the domain listed in the return path of an email. Legitimate newsletters might use web bugs, although many consider this an invasion of privacy. Best thing to do is report the message via the Junk add-in and open a support case to have it properly investigated. Based on your mentioned description about "SPF authentication fails for our outbound emails sent by Exchange Online despite having this DNS record : v=spf1 include:spf.protection.outlook.com -all", once could you please provide us your detailed error message screenshot, your SPF record and domain via private message? Also, the original destination recipient will get an E-mail notification, which informs him that a specific E-mail message that was sent to him was identified as Spoof mail and for this reason didnt automatically send to his mailbox. Q2: Why does the hostile element use our organizational identity? Scenario 1 the sender uses an E-mail address that includes a domain name of a well-known organization. See You don't know all sources for your email. ASF specifically targets these properties because they're commonly found in spam. Recipient mail systems refer to the SPF TXT record to determine whether a message from your custom domain comes from an authorized messaging server. In many scenarios, the spoofed E-mail message will not be blocked even if the SPF value marked as Fail because of the tendency to avoid a possible event of false positives. We don't recommend that you use this qualifier in your live deployment. If you're using IPv6 IP addresses, replace ip4 with ip6 in the examples in this article. Join the movement and receive our weekly Tech related newsletter. The SPF Fail policy article series included the following three articles: Q1: How does the Spoof mail attack is implemented? You can also specify IP address ranges using CIDR notation, for example ip4:192.168.0.1/26. Nearly all large email services implement traditional SPF, DKIM, and DMARC checks. Text. Getting Started with PDQ Deploy & Inventory, Automatically assign licenses in Office 365, Match all domain name records (A and AAAA), Match all listed MX records. The SPF sender verification can mark a particular E-mail message with a value to SPF = none or SPF = Fail. Disable SPF Check On Office 365. Customers on US DC (US1, US2, US3, US4 . Messages that use JavaScript or Visual Basic Script Edition in HTML are marked as high confidence spam. The meaning of the SPF = Fail is that we cannot trust the mail server that sends the E-mail message on behalf of the sender and for this reason, we cannot trust the sender himself. Ensure that you're familiar with the SPF syntax in the following table. In all Microsoft 365 organizations, the Advanced Spam Filter (ASF) settings in anti-spam policies in EOP allow admins to mark messages as spam based on specific message properties. Usually, this is the IP address of the outbound mail server for your organization. Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type. If you don't have a deployment that is fully hosted in Microsoft 365, or you want more information about how SPF works or how to troubleshoot SPF for Microsoft 365, keep reading. However, the industry is becoming more aware about issues with unauthenticated email, particularly because of the problem of phishing. Domain names to use for all third-party domains that you need to include in your SPF TXT record. You will also need to watch out for the condition where you SPF record contains more than 10 DNS lookups, and take action to fix it when it happens. office 365 mail SPF Fail but still delivered, Re: office 365 mail SPF Fail but still delivered. For instructions, see Gather the information you need to create Office 365 DNS records. We recommend the value -all. If you haven't already done so, form your SPF TXT record by using the syntax from the table. If you do not use any external third-party email services and route all your emails via Office 365, your SPF record will have the following syntax: v=spf1 include:spf.protection.outlook.com -all.