These scripting languages are used in email messages to cause specific actions to automatically occur. This type of scenario, there is a high chance that we are experiencing a Spoof mail attack! Edit Default > advanced optioins > Mark as Spam > SPF record: hard fail: Off. For questions and answers about anti-spam protection, see Anti-spam protection FAQ. 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). Basically, SPF, along with DKIM, DMARC, and other technologies supported by Office 365, help prevent spoofing and phishing. What does SPF email authentication actually do? Below is an example of adding the office 365 SPF along with onprem in your public DNS server. However, there is a significant difference between this scenario. In case that your organization experiences a scenario in which your mail server IP address, In the current article and the next article: My E-mail appears as spam | Troubleshooting, In the current article, we will review how to deal with Spoof mail by creating, Your email address will not be published. The obvious assumption is that this is the classic scenario of Spoof mail attack and that the right action will be to block automatically or reject the particular E-mail message. This record probably looks like this: If you're a fully hosted customer, that is, you have no on-premises mail servers that send outbound mail, this is the only SPF TXT record that you need to publish for Office 365. You can't report messages that are filtered by ASF as false positives. is required for every domain and subdomain to prevent attackers from sending email claiming to be from non-existent subdomains. Anti-spoofing protection considers both SPF hard fails and a much wider set of criteria. This is implemented by appending a -all mechanism to an SPF record. SPF helps validate outbound email sent from your custom domain (is coming from who it says it is). 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. SPF records in Office 365 are DNS records that help authenticate Office 365 based emails so organizations can operate with higher levels of trust and prevent spoofing. To do this, contoso.com publishes an SPF TXT record that looks like this: When the receiving server sees this record in DNS, it also performs a DNS lookup on the SPF TXT record for contoso.net and then for contoso.org. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. From my experience, the phase is fascinating because after we activate the monitor process, we will usually find an absorbing finding of: Based on this information, we will be able to understand the real scope of the problem, the main characters of this attack and so on. First, we are going to check the expected SPF record in the Microsoft 365 Admin center. Scenario 1. Disable SPF Check On Office 365. For example: Once you've formulated your SPF TXT record, follow the steps in Set up SPF in Microsoft 365 to help prevent spoofing to add it to your domain. (e.g., domain alignment for SPF); d - send only if DKIM fails; s - send only when SPF fails. The reason for the outcome of SPF = Fail is related to a missing configuration on the sending mail infrastructure., The E-mail address of the sender, uses the domain name of, The result from the SPF sender verification test is , The popular organization users who are being attacked, The various types of Spoofing or Phishing attacks, The E-mail address of the sender includes our domain name (in our specific scenario; the domain name is, The result of the SPF sender verification check is fail (SPF = Fail). Most end users don't see this mark. In other words, using SPF can improve our E-mail reputation. Q9: So how can I activate the option to capture events of an E-mail message that have the value of SPF = Fail? This article describes how to update a Domain Name Service (DNS) record so that you can use Sender Policy Framework (SPF) email authentication with your custom domain in Office 365. 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. Keeping track of this number will help prevent messages sent from your organization from triggering a permanent error, called a perm error, from the receiving server. Login at admin.microsoft.com Navigate to your domain - Expand Settings and select Domains - Select your custom Domain (not the <companyname>.onmicrosoft.com domain Lookup the SPF Record Click on the DNS Records tab. Although SPF is designed to help prevent spoofing, but there are spoofing techniques that SPF can't protect against. Best thing to do is report the message via the Junk add-in and open a support case to have it properly investigated. For example, in case that we need to Impose a strict security policy, we will not be willing to take the risk, and in such scenario, we will block the E-mail message, send the E-mail to quarantine or forward the E-mail to a designated person that will need to examine the E-mail and decide if he wants to release the E-mail or not. Indicates soft fail. You can also specify IP address ranges using CIDR notation, for example ip4:192.168.0.1/26. Messages sent from Microsoft 365 to a recipient within Microsoft 365 will always pass SPF. One option that is relevant for our subject is the option named SPF record: hard fail. 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. Despite that the first association regarding the right response to an event in which the sender uses an E-mail address that includes our organization domain name + the result from the SPF sender verification test is fail, is to block and delete such E-mails; I strongly recommend not doing so. by How to enforce SPF fail policy in Office 365 (Exchange Online) based environment, The main two purposes of using SPF mechanism, Scenario 1: Improve our E-mail reputation (domain name), Scenario 2: Incoming mail | Protect our users from Spoof mail attack, The popular misconception relating to SPF standard. You can read a detailed explanation of how SPF works here. The following examples show how SPF works in different situations. Summary: This article describes how Microsoft 365 uses the Sender Policy Framework (SPF) TXT record in DNS to ensure that destination email systems trust messages sent from your custom domain. This tag allows the embedding of different kinds of documents in an HTML document (for example, sounds, videos, or pictures). The element which needs to be responsible for capturing event in which the SPF sender verification test considered as Fail is our mail server or the mail security gateway that we use. Scenario 2. Authentication-Results: spf=none (sender IP is 118.69.226.171) smtp.mailfrom=kien.ngan; thakrale5.onmicrosoft.com; dkim=none (message not signed) header.d=none;thakrale5.onmicrosoft.com; dmarc=none action=none header.from=thakrale5.onmicrosoft.com; Received-SPF: None (protection.outlook.com: kien.ngan does not designate permitted sender hosts) Although there are other syntax options that are not mentioned here, these are the most commonly used options. I hate spam to, so you can unsubscribe at any time. today i received mail from my organization. However, there are some cases where you may need to update your SPF TXT record in DNS. Most of the mail infrastructures will leave this responsibility to us meaning the mail server administrator. Normally you use the -all element which indicates a hard fail. This type of configuration can lead us to many false-positive events, in which E-mail message that sent from our customer or business partner can be identified as spam mail. For example, let's say that your custom domain contoso.com uses Office 365. In this phase, we are only capturing event in which the E-mail address of the sender uses the domain name of our organization, and also; the result from the SPF sender verification test is Fail. A typical SPF TXT record for Microsoft 365 has the following syntax: v=spf1 is required. 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. The main reason that I prefer to avoid the option of using the Exchange Online spam filter option is because, this option doesnt distinguish between a scenario in which the sender uses our domain name as part of his E-mail address vs. a scenario in which the sender uses E-mail address, which doesnt include our domain name. 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.. 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. A typical SPF TXT record for Microsoft 365 has the following syntax: text v=spf1 [<ip4>|<ip6>:<IP address>] [include:<domain name>] <enforcement rule> For example: text v=spf1 ip4:192.168..1 ip4:192.168..2 include:spf.protection.outlook.com -all where: v=spf1 is required. What happens to the message is determined by the Test mode (TestModeAction) value: The following Increase spam score ASF settings result in an increase in spam score and therefore a higher chance of getting marked as spam with a spam confidence level (SCL) of 5 or 6, which corresponds to a Spam filter verdict and the corresponding action in anti-spam policies. A4: The sender E-mail address, contains information about the domain name (the right part of the E-mail address). No. The following Mark as spam ASF settings set the SCL of detected messages to 6, which corresponds to a Spam filter verdict and the corresponding action in anti-spam policies. This tool checks your complete SPF record is valid. Use the step-by-step instructions for updating SPF (TXT) records for your domain registrar. and are the IP address and domain of the other email system that sends mail on behalf of your domain. Q3: What is the purpose of the SPF mechanism? This record works for just about everyone, regardless of whether your Microsoft datacenter is located in the United States, or in Europe (including Germany), or in another location. Required fields are marked *. 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). Default value - '0'. If you still like to have a custom DNS records to route traffic to services from other providers after the office 365 migration, then create an SPF record for . This is because the receiving server cannot validate that the message comes from an authorized messaging server. The defense action that we will choose to implement in our particular scenario is a process in which E-mail message that identified as Spoof mail, will not be sent to the original destination recipient.. Notify me of followup comments via e-mail. 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. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. See Report messages and files to Microsoft. In each of these scenarios, if the SPF sender verification test value is Fail the E-mail will mark as spam. Figure out what enforcement rule you want to use for your SPF TXT record. Some services have other, more strict checks, but few go as far as EOP to block unauthenticated email and treat them as spoofed messages. SRS only partially fixes the problem of forwarded email. In this step, we want to protect our users from Spoof mail attack. Domain administrators publish SPF information in TXT records in DNS. For advanced examples and a more detailed discussion about supported SPF syntax, see How SPF works to prevent spoofing and phishing in Office 365. The 6 commonly used elements in an SPF record are: You can add as many include: or ip4: elements to your SPF record as you need. After a specific period, which we allocate for examining the information that collected, we can move on to the active phase, in which we execute a specific action in a scenario that the Exchange rule identifies an E-mail message that is probably Spoof mail. The meaning is a hostile element that executes spoofing or Phishing attacks and uses a sender E-mail address that includes our domain name. This is where we use the learning/inspection mode phase and use it as a radar that helps us to locate anomalies and other infrastructure security issues. office 365 mail SPF Fail but still delivered Hello today i received mail from my organization. If you have anti-spoofing enabled and the SPF record: hard fail (MarkAsSpamSpfRecordHardFail) turned on, you will probably get more false positives. The interesting thing is that in Exchange-based environment, we can use very powerful Exchange server feature named- Exchange rule, for identifying an event in which the SPF sender verification test result is Fail, and define a response respectively. Use the 90-day Defender for Office 365 trial at the Microsoft 365 Defender portal trials hub. The receiving server may also respond with a non-delivery report (NDR) that contains an error similar to these: Some SPF TXT records for third-party domains direct the receiving server to perform a large number of DNS lookups. More info about Internet Explorer and Microsoft Edge. It is published as a Domain Name System (DNS) record for that domain in the form of a specially formatted TXT record. Share. The event in which the SPF sender verification test result is Fail, can be realized in two main scenarios. We recommend that you disable this feature as it provides almost no additional benefit for detecting spam or phishing message, and would instead generate mostly false positives. The presence of filtered messages in quarantine. Join the movement and receive our weekly Tech related newsletter. Specifically, the Mail From field that . 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. Solution: Did you try turning SPF record: hard fail on, on the default SPAM filter? All SPF TXT records start with this value, Office 365 Germany, Microsoft Cloud Germany only, On-premises email system. You will first need to identify these systems because if you dont include them in the SPF record, mail sent from those systems will be listed as spam. Microsoft Office 365. SPF sender verification check fail | our organization sender identity. 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. ASF specifically targets these properties because they're commonly found in spam. 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. Sender Policy Framework, or SPF, is an email authentication technique that helps protect email senders and recipients from spam, phishing and spoofing. Messages that hard fail a conditional Sender ID check are marked as spam. The following Mark as spam ASF settings set the SCL of detected messages to 9, which corresponds to a High confidence spam filter verdict and the corresponding action in anti-spam policies. There is no right answer or a definite answer that will instruct us what to do in such scenarios. When this setting is enabled, any message that hard fails a conditional Sender ID check is marked as spam. The setting is located at Exchange admin Center > protection > spam filter > double click Default > advanced options > set SPF record: hard fail: off. Use trusted ARC Senders for legitimate mailflows. For instructions, see Gather the information you need to create Office 365 DNS records. Despite my preference for using Exchange rule as preferred tool for enforcing the required SPF policy, I would also like to mention an option that is available for Office 365 customers, which their mail infrastructure based on Exchange Online and EOP (Exchange Online Protection). For example: Previously, you had to add a different SPF TXT record to your custom domain if you were using SharePoint Online. Received-SPF: Fail (protection.outlook.com: domain of mydomain.com does not designate 67.220.184.98 as permitted sender) receiver=protection.outlook.com; why spffailed mails normally received? Typically, email servers are configured to deliver these messages anyway. IP address is the IP address that you want to add to the SPF TXT record. The rest of this article uses the term SPF TXT record for clarity. . Jun 26 2020 In reality, most of the organization will not implement such a strict security policy because they would prefer to avoid a false-positive scenario in which a legitimate mail mistakenly identified as Spoof mail. All SPF TXT records end with this value. To be able to use the SPF option we will need to implement by ourselves the following proceeds: Add to the DNS server that hosts our domain name the required SPF record, and verifies that the syntax of the SPF record is correct + verify that the SPF record includes information about all the entities that send an E-mail message on behalf of our domain name. The SPF information identifies authorized outbound email servers. 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. For more information, see Example: SPF TXT record for multiple outbound on-premises mail servers and Microsoft 365. domain name is the domain you want to add as a legitimate sender. The enforcement rule indicates what the receiving mail system should do with mail sent from a server that isnt listed in the SPF record. Instead, ensure that you use TXT records in DNS to publish your SPF information. Need help with adding the SPF TXT record? Customers on US DC (US1, US2, US3, US4 . For a list of domain names you should include for Microsoft 365, see External DNS records required for SPF. In this example, the SPF rule instructs the receiving email server to only accept mail from these IP addresses for the domain contoso.com: This SPF rule tells the receiving email server that if a message comes from contoso.com, but not from one of these three IP addresses, the receiving server should apply the enforcement rule to the message. In each of the above scenarios, the event in which the SPF sender verification test ended with SPF = Fail result is not good. 2. The Exchange incident report includes a summary of the specific mail flow, such as the name of the sender, recipient, and the Exchange rule that was activated and also; we can ask to include an attachment of the original E-mail message that was captured.. Microsoft maintains a dynamic but non-editable list of words that are associated with potentially offensive messages. @tsulaI solved the problem by creating two Transport Rules. In the next article, Implementing SPF Fail policy using Exchange Online rule (dealing with Spoof E-mail attack) | Phase 1 learning mode | Part 2#3, we will review the step-by-step instruction needed to create an Exchange Online rule that will help us to monitor such events. 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. A2: The purpose of using the identity of one of our organization users is because, there is a high chance that the Innocent victim (our organization user), will tend to believe someone he knows vs. some sender that he doesnt know (and for this reason tends to trust less).