Ransomware attacks are soaring and phishing and email impersonation attacks are being conducted at unprecedented levels. Cybersecurity defenses are being tested like never before.

Large enterprises are big targets as they store vast quantities of personal data which can be used for identity theft. Retailers are being attacked to obtain credit/debit card information and attacks on hospitals provide sensitive health data that can be used for medical identity theft.

Small businesses are not such an attractive target, but they do store reasonable amounts of customer data and attacks can still be profitable. A successful attack on Walmart would be preferable, but attacks on SMBs are far easier to pull off. SMBs typically do not have the budgets to invest in cybersecurity and often leave gaps that can be easily exploited by cybercriminals.

One of the most common methods of attacking SMBs is phishing. If a phishing email makes it to an inbox, there is a reasonable chance that the message will be opened, the requested action taken and, as a result, credentials will be compromised or malware will be installed.

The 2018 KnowBe4 Phishing Industry Benchmarking Report shows that on average, the probability of an employee clicking on a malicious hyperlink or taking another fraudulent request is 27%. That means one in four employees will click a link in a phishing email or obey a fraudulent request.

Email impersonation attacks are often successful. They involve sending an email to an individual or small group in an organization with a plausible request. The sender of the message is spoofed so the email appears to have been sent from a known individual or company. The email will use a genuine email address on a known business domain. Without appropriate security controls in place, that message will arrive in inboxes and several employees are likely to click and disclose their credentials or open an infected email attachment and install malware. Most likely, they will not realize they have been scammed.

One method that can be used to prevent these spoofed messages from being delivered is to apply Domain-based Message Authentication, Reporting and Conformance (DMARC) rules. In a nutshell, DMARC consists of two technologies – Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM).

SPF is a DNS-based filtering control that helps to identify spoofed messages. SPF sets authorized sender IP addresses on DNS servers. Recipient servers perform lookups on the SPF records to make sure that the sender IP matches one of the authorized vendors on the organization’s DNS servers. If there is a match the message is delivered. If the check fails, the message is rejected or quarantined.

DKIM involves the use of an encrypted signature to verify the sender’s identity. That signature is created using the organization’s public key and is decrypted using the private key available to the email server. DMARC rules are then applied to either reject or quarantine messages that fail authentication checks. Quarantining messages is useful as it allows administrators to check to make sure the genuine emails have not been flagged incorrectly.

Reports can be generated to monitor email activity and administrators can see the number of messages that are being rejected or dropped. A sudden increase in the number of rejected messages indicates an attack is in progress.

DMARC is not a silver bullet that will stop all email impersonation and phishing attacks. It is an extra layer of security that can greatly reduce the number of threats that arrive in inboxes.

TitanHQ’s anti-phishing and anti-spam solution – SpamTitan – incorporates DMARC to protect against email impersonation attacks along with advanced anti-malware features, including a Bitdefender-powered sandbox.

For further information securing your email channel and blocking email-based threats, contact TitanHQ today.