Whats SPF?

SPF (Sender Policy Framework AKA “RFC 7208”) is an email authentication protocol that helps verify the authenticity of the sender’s domain and is one step out of few that help us avoid email phishing attacks. It allows domain owners to specify which mail servers are authorized to send emails on behalf of their domain. SPF works by publishing a DNS (Domain Name System) record that lists the approved IP addresses or hostnames of the authorized mail servers.

When an email is received, the recipient’s mail server can check the SPF record of the sender’s domain to verify if the email originated from an authorized server. The SPF record contains information that defines the allowed sending sources for a particular domain. If the sending server’s IP address or hostname matches the entries in the SPF record, the email passes the SPF authentication.

SPF helps prevent email spoofing and forgery by ensuring that emails claiming to be from a specific domain are sent from approved sources. It provides a mechanism for email receivers to check if the email’s origin aligns with the domain’s published SPF record, reducing the risk of accepting fraudulent emails.

How SPF works?

Let’s say the domain example.com wants to implement SPF. The domain owner publishes an SPF record in their DNS (Domain Name System) records, specifying the authorized mail servers that can send emails on behalf of the domain. The SPF record may look like this:

“v=spf1 ip4:192.3.1.0/24 ip4:198.22.200.123 a -all”

In this example, the SPF record includes two IP addresses (ip4) and an A record (a). These mechanisms indicate that emails originating from IP addresses within the specified range or from the designated mail server are allowed. The “-all” at the end specifies a strict policy that any other source should result in a failed SPF check.

Now, when an email is received, the recipient’s mail server performs an SPF check by querying the DNS records of the sender’s domain. It retrieves the SPF record for example.com and verifies whether the IP address of the sending server matches the authorized sources defined in the SPF record.

If the sender’s IP address matches the authorized sources, the SPF check passes, indicating that the email is likely legitimate. However, if the sender’s IP address doesn’t match the authorized sources or if there is no SPF record, the SPF check fails. Depending on the recipient’s SPF policy, the email may be marked as spam, rejected, or subjected to further scrutiny.

By implementing SPF, domain owners can protect their domain from being used in email forgery and unauthorized email sending. It allows email recipients to verify the authenticity of the sender’s domain, making it more difficult for spammers and scammers to deceive recipients.

Note that SPF is just one component of email authentication and one subject out of many when it comes down to information security in your organization. It works alongside other methods such as DKIM (DomainKeys Identified Mail) and DMARC (Domain-based Message Authentication, Reporting, and Conformance) to provide a comprehensive email authentication framework.

Whats SPF Video

By implementing SPF(RFC 7208), domain owners can strengthen email security, reduce the risk of domain spoofing, and improve email deliverability. It helps recipients distinguish between legitimate emails and those sent from unauthorized sources, contributing to the prevention of phishing attacks and email fraud.

SPF Flattening Tools

Besides of implementation of SPF. We also want to implement a flattening tool to avoid the lookup limit 10 that comes with the RFC 7208 policy. Sender Policy Framework (SPF) flattening is a technique designed to streamline and optimize SPF records, reducing the number of DNS look-ups required for SPF validation. An SPF flattening tool automates this process, making it easier to manage SPF records effectively.

SPF records are used to authenticate email senders, helping to prevent email spoofing and unauthorized use of a domain’s identity. However, when an SPF record contains multiple “include” mechanisms or redirects to other domains, each of these mechanisms or redirects necessitates a separate DNS look-up. This can lead to performance issues and, in some cases, encounter DNS look-up limits.

DNS look-up limits are a constraint imposed by DNS providers as part of the RFC 7208 policy or resolvers that restrict the number of DNS queries that can be made within a specific timeframe to avoid DDOS attack. These limits are meant to prevent abuse and excessive load on DNS infrastructure. For example, a look-up limit of 10 means that only ten DNS look-ups can be made for SPF validation during a specific time interval.

To address these challenges, SPF flattening consolidates all the included domains within an SPF record into a single record. By doing so, the need for multiple DNS look-ups is eliminated, improving performance and mitigating potential DNS look-up limit issues.

When using an SPF flattening tool, the tool analyzes the original SPF record, follows each include mechanism or redirect, retrieves the SPF records of the included domains, and constructs a flattened SPF record that combines all the mechanisms into one. This flattened record is then published in the DNS.

Implementing SPF flattening reduces the number of DNS look-ups required, leading to faster SPF validation and improved email delivery. It also helps ensure compliance with DNS look-up limits imposed by DNS providers or resolvers.

However, it’s crucial to exercise caution when employing SPF flattening as it can result in longer SPF records that might exceed the DNS’s maximum record length limit. Additionally, because SPF flattening creates a static flattened record, any changes to the SPF policies of the included domains may render the flattened record outdated, requiring manual updates.

SPF flattening tools simplify the management and optimization of SPF records, aiding domain owners in the implementation and maintenance of SPF-based email authentication, we want to implement SPF flattening tools as part of our overall information security management to protect our company email servers and prevent email phishing attacks. By reducing DNS look-ups and addressing look-up limits, SPF flattening contributes to more efficient email delivery and improved email security.

Why Verify Sender Identification?

Identification of sender can be crucial as many business and organizations use various communication tools and services to perform and act on important business and high risk financial decisions base on incoming information. if those are at risk to be faked and fabricated, or for example an act of malicious spoofing attacks can result in huge damage for a company.

1. Prevention of Spoofing

Email spoofing is a technique where attackers forge the sender’s address to make an email appear as if it is from a legitimate source. This can lead to phishing attacks, where users are tricked into providing sensitive information. SPF helps to mitigate this risk by allowing receiving mail servers to verify that incoming emails are from authorized servers, reducing the chances of successful spoofing attemptsing Email Deliverability** When SPF is properly configured, it can improve email deliverability rates. Legitimate emails are less likely to be flagged as spam or rejected by receiving servers. By establishing a clear set of rules about which servers can send emails on behalf of a domain, SPF helps ensure that legitimate communications reach their intended recipients .

3. Builpients

Verifying sender identification through SPF can enhance trust with recipients. When organizations implement SPF and other email authentication protocols, they signal to their users that they take security seriously. This can increase the likelihood that recipients will engage with the content of the emails they receive .

4. Compliance with Securits

Many regulatory frameworks and industry standards require organizations to implement measures to protect against email fraud. SPF is a foundational step in establishing a robust email security posture that can help organizations comply with these standards.

What Are Spoofing Attacks

Spoofing attacks involve tricking a recipient into believing that a message comes from a legitimate source when it actually originates from an unauthorized sender. This is often achieved by forging the sender’s email address in the message header. Spoofing can lead to various malicious activities, including phishing, identity theft, and the distribution of malware.

Key Types of Spoofing Attacks:
Email Spoofing: This is the most common type of spoofing. Attackers manipulate the “From” field of an email to make it look like it’s coming from a trusted source, such as a bank or a colleague. The goal is to deceive recipients into providing sensitive information, clicking on malicious links, or downloading harmful attachments​.

Website Spoofing: Attackers create a fake website that resembles a legitimate one to trick users into entering personal information, such as login credentials or credit card numbers. This often occurs alongside phishing emails that direct users to the spoofed site​

IP Spoofing: In this scenario, attackers send packets from a false (or “spoofed”) IP address to disguise their identity or to bypass security measures. This method can be used in Distributed Denial of Service (DDoS) attacks to overwhelm a target server​.

Why Spoofing is Dangerous:
Phishing Attacks: Spoofed emails often lead to phishing attacks, where recipients are tricked into revealing sensitive information. These attacks can have severe consequences, including financial loss and data breaches​.

Reputation Damage: Organizations whose identities are spoofed may suffer repetitional damage, as their customers may lose trust in them if they fall victim to these attacks​
Malware Distribution: Spoofed emails can contain links or attachments that distribute malware, leading to further security incidents within an organization​

Verifying the sender is a crucial and important action needs to be taken by relevant security holders within the company. and in some cases, there’s needs to be further verification of a sender due to the impact of decisions following an email, message or any kind of information.