300-720 Securing Email with Cisco Email Security Appliance (300-720 SESA) Questions and Answers

• Public/Private keypair. A public/private keypair is a pair of cryptographic keys that are used to generate and verify digital signatures. The private key is used to sign the email message, while the public key is used to verify the signature. The public key is published in a DNS record, while the private key is stored on the Cisco Secure Email Gateway appliance[1, p. 2].
• Domain signing profile. A domain signing profile is a configuration that specifies the domain and selector to use for signing outgoing messages, as well as the signing algorithm, canonicalization method, and header fields to include in the signature. You can create multiple domain signing profiles for different domains or subdomains[1, p. 3].

The other options are not valid because:

• A. DMARC verification profile is not a component for utilizing a digital signature in outgoing emails. It is a component for verifying the authenticity of incoming emails based on SPF and DKIM results[2, p. 1].
• B. SPF record is not a component for utilizing a digital signature in outgoing emails. It is a component for validating the sender IP address of incoming emails based on a list of authorized IP addresses published in a DNS record[3, p. 1].
• E. PKI certificate is not a component for utilizing a digital signature in outgoing emails. It is a component for encrypting and decrypting email messages based on a certificate authority that issues and validates certificates[4, p. 1].

Overview of Encrypting Communication with Other MTAs:

AsyncOS supports the STARTTLS extension to SMTP (Secure SMTP over TLS).

The TLS implementation in AsyncOS provides privacy through encryption.

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ceo@example.com is the data that must be added to the dictionary to accomplish this goal. A content dictionary is a list of values that can be used as a condition in a content filter or a message filter. Forged Email Detection is a feature that allows Cisco ESA to detect and prevent email spoofing attacks, where the sender’s address or domain is forged to appear as someone else, such as the CEO of the organization.

To create a content dictionary for use with Forged Email Detection on Cisco ESA, the administrator can follow these steps:

• Select Mail Policies > Content Dictionaries and click Add Dictionary.
• Enter a name and description for the content dictionary, such as CEO Email.
• Under Dictionary Values, click Add Value.
• Enter the email address of the CEO, such as ceo@example.com.
• Click Submit.

• System: This is the default list of trusted certificate authorities that is provided by Cisco and updated automatically. It contains the certificates of well-known and widely used certificate authorities, such as VeriSign, Thawte, and GoDaddy.
• Custom: This is the list of additional certificate authorities that you can add manually or import from a file. It allows you to trust certificates that are issued by your own or third-party certificate authorities that are not included in the system list.

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According to the User Guide for AsyncOS 12.0 for Cisco Email Security Appliances2, the order of virus scanning when multilayer antivirus scanning is configured is as follows:

• The McAfee engine scans the message first. If the McAfee engine detects a virus, the message is dropped or repaired, depending on the configuration. If the McAfee engine does not detect a virus, the message is passed to the next layer of scanning.
• The Sophos engine scans the message second. If the Sophos engine detects a virus, the message is dropped or repaired, depending on the configuration. If the Sophos engine does not detect a virus, the message is delivered to the recipient.

To ensure that executive messages are originating from legitimate sending addresses, the administrator must take two steps:

• Create an incoming content filter with the Forged Email Detection condition. This will allow the administrator to detect and block messages that have a forged “From: header” that matches or is similar to any of the names in a content dictionary.
• Create a content dictionary including a list of the names that are being spoofed. This will allow the administrator to specify the names of the executives that are being targeted by spoofing attacks and use them in the Forged Email Detection condition. The other options are not relevant or sufficient for this task. References: [Cisco Secure Email Gateway Administrator Guide - Forged Email Detection] and [Cisco Secure Email Gateway Administrator Guide - Creating Content Dictionaries]

The appliance enforces your organization’s policies for messages sent to and from your users through the use of mail policies. These are sets of rules that specify the types of suspect, sensitive, or malicious content that your organization may not want entering or leaving your network. This content may include:

-spam

-legitimate marketing messages

-graymail

-viruses

-phishing and other targeted mail attacks

-confidential corporate data

-personally identifiable information

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• System: This is the default list of trusted certificate authorities that is provided by Cisco and updated automatically. It contains the certificates of well-known and widely used certificate authorities, such as VeriSign, Thawte, and GoDaddy.
• Custom: This is the list of additional certificate authorities that you can add manually or import from a file. It allows you to trust certificates that are issued by your own or third-party certificate authorities that are not included in the system list.

Determining Which Interface is Used for Mail Delivery Unless you specify the output interface via the deliveryconfig command or via a message filter ( alt-src-host ), or through the use of a virtual gateway, the output interface is selected by the AsyncOS routing table. https://www.cisco.com/c/en/us/td/docs/security/esa/esa11-1/user_guide/b_ESA_Admin_Guide_11_1/b_ESA_Admin_Guide_chapter_011001.html?bookSearch=true

By modifying the mail policies, specifically the recipient matching criteria, you can ensure that email recipients do not match multiple policies simultaneously. When recipients in the email message belong to different domains (e.g., cisco.com and test.com), it can result in multiple policies being triggered simultaneously, leading to inconsistent delivery of emails with attachments.

DLP is for outgoing mail only and not relevant to incoming mail.

Secure unsubscribe option for end users. Mimicking an unsubscribe option is a popular phishing technique. For this reason, the end users are generally wary of clicking unknown unsubscribe links. For such scenarios, the cloud-based Unsubscribe Service extracts the original unsubscribe URI, checks the reputation of the URI, and then performs the unsubscribe process on behalf of the end user. This protects end users from malicious threats masquerading as unsubscribe links. https://www.cisco.com/c/en/us/td/docs/security/esa/esa14-2-1/User_Guide/b_ESA_Admin_Guide_14-2-1/b_ESA_Admin_Guide_12_1_chapter_01110.html#id_101033

Content filter is a component on a Cisco Secure Email Gateway that must be configured to catch attachments, including credit card numbers, and hold them for review until further action is taken. Content filter allows you to define rules based on message content and apply actions such as quarantine, encrypt, or modify. References = [User Guide for AsyncOS 12.0 for Cisco Email Security Appliances - GD (General Deployment) - Content Filters [Cisco Secure Email Gateway] - Cisco]

Spam threshold is a setting that determines the minimum score that a message must have to be classified as spam by Cisco ESA. The lower the threshold, the more aggressive the spam detection is.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 6-5.

Geolocation-based filtering and senderbase reputation filtering are two features of Cisco Email Security that can be added to a Sender Group to protect an organization against email threats. Geolocation-based filtering allows Cisco ESA to accept or reject connections from email servers based on their geographic location, such as country or continent. Senderbase reputation filtering allows Cisco ESA to reject or throttle connections from email servers based on their reputation score, which is calculated by Talos using sensor information from various sources.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 5-4 and page 6-2.

According to the [Cisco Secure Email User Guide], Non-Viral threat detection is a feature of Outbreak Filters that detects and blocks email messages that contain non-viral threats such as phishing, fraud, or social engineering[1, p. 25]. To use this feature, you need to enable either AntiSpam or Intelligent Multi-Scan on your Cisco Secure Email Gateway, as these features provide the necessary scanning and filtering capabilities for Non-Viral threat detection[1, p. 26].

The other options are not valid because:

• A. Non-Viral threat detection does not require Antivirus or AMP enablement to properly function. Antivirus and AMP are features that detect and block email messages that contain viral threats such as malware or ransomware[1, p. 27-28].
• B. The Outbreak Filters option Graymail Header does not affect Non-Viral threat detection. Graymail Header is an option that allows you to add a header to email messages that are classified as graymail, which are messages that are not spam but may be unwanted by some recipients, such as newsletters or promotions[1, p. 25].
• D. The Outbreak Filters option URL Rewriting does not affect Non-Viral threat detection. URL Rewriting is an option that allows you to rewrite the URLs in email messages to point to a Cisco proxy server, which can scan the URLs for malicious content and redirect the users to a warning page if needed[1, p. 25].

To enable domain protection for the organization, the administrator must configure an outgoing mail policy that matches the sender and the from headers of the email. The sender header is the envelope sender address that is used by SMTP to route the email. The from header is the address that is displayed to the recipient as the source of the email. These headers are used to generate and verify a DomainKeys Identified Mail (DKIM) signature, which is a cryptographic method of validating the authenticity and integrity of an email message.

The other headers are not relevant for domain protection. The message-ID header is a unique identifier for each email message. The URL reputation header is a score that indicates the likelihood of a URL being malicious. The mail-from header is an alias for the sender header.

With DomainKeys or DKIM email authentication, the sender signs the email using public key cryptography. Configuring DomainKeys and DKIM Signing A signing key is the private key stored on the appliance. https://www.cisco.com/c/en/us/td/docs/security/esa/esa11-1/user_guide/b_ESA_Admin_Guide_11_1/b_ESA_Admin_Guide_chapter_010101.html?bookSearch=true

Spam Quarantine End-User Authentication Query is a query that Cisco ESA performs against an LDAP server to validate the end-user credentials during login to the End-User Quarantine.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 10-9.

To combat backscatter, which is a type of spam that consists of bounce messages sent to forged sender addresses, the administrator must enable the Bounce Verification feature under Security Settings. This feature allows the appliance to verify whether a bounce message is legitimate or not by checking if the original message was sent from the appliance. If not, the bounce message is considered as backscatter and can be dropped or quarantined. References: [Cisco Secure Email Gateway Administrator Guide - Configuring Bounce Verification]

Table Description automatically generated

Spam threshold is a setting that determines the minimum score that a message must have to be classified as spam by Cisco ESA. The lower the threshold, the more aggressive the spam detection is.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 6-5.

The maximum message size that can be configured for encryption on the Cisco ESA is 25 MB. This is the default value for the Maximum Message Size for Encryption setting in the Encryption Profile. Messages that exceed this size will not be encrypted and will be delivered as normal.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 12-6.

Custom policy is a type of DLP policy template that must be used to create a policy that meets this requirement. Custom policy allows the administrator to define their own criteria for detecting sensitive or confidential data in messages, such as keywords, regular expressions, file types, etc.

To create a custom DLP policy on Cisco ESA, the administrator can follow these steps:

• Select Mail Policies > DLP Policy Manager and click Add Policy.
• Enter a name and description for the DLP policy, such as Patent Protection.
• Under Policy Template, select Custom Policy.
• Click Submit.
• Under Content Matching Criteria, click Add Criteria.
• Choose a matching type, such as Keyword or Regular Expression, and enter a value that matches the proprietary patent documents, such as “patent number” or “\d{4}/\d{6}”.
• Click Submit.

The other options are not valid types of DLP policy templates to create a policy that meets this requirement, because they are predefined templates that do not match the proprietary patent documents.

References: [User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway], page 9-3 and page 9-5.

To use DKIM for outbound email, the administrator must export the DNS TXT record from the Cisco Secure Email Gateway and provide it to the DNS registrar of the domain. This will allow the recipient servers to verify the DKIM signature of the email by querying the DNS record of the sender domain. References: [Cisco Secure Email Gateway Administrator Guide - Configuring DKIM Signing]

Geolocation-based filtering and senderbase reputation filtering are two features of Cisco Email Security that can be added to a Sender Group to protect an organization against email threats. Geolocation-based filtering allows Cisco ESA to accept or reject connections from email servers based on their geographic location, such as country or continent. Senderbase reputation filtering allows Cisco ESA to reject or throttle connections from email servers based on their reputation score, which is calculated by Talos using sensor information from various sources.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 5-4 and page 6-2.

Condition is a component that must be added to the content filter to trigger on failed SPF Verification or DKIM Authentication verdicts. Condition is a criterion that determines whether a message matches a content filter rule or not, such as message size, sender address, attachment type, etc.

To add a condition to the content filter that triggers on failed SPF Verification or DKIM Authentication verdicts, the administrator can follow these steps:

• Select Mail Policies > Content Filters and click Add Filter.
• Enter a name and description for the content filter.
• Under Conditions, click Add Condition.
• Choose SPF Verification or DKIM Authentication from the drop-down menu.
• Choose Fail from the drop-down menu.
• Click Submit.

The other options are not valid components to trigger on failed SPF Verification or DKIM Authentication verdicts, because they are not part of content filters.

References: [User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway], page 8-3 and page 8-4.

When CRES (Cisco Registered Envelope Service) is unavailable, Cisco ESA will requeue the message and attempt to resend it later, until the maximum number of retries or the maximum age of the message is reached. The message will not be sent in clear text, dropped, or encrypted by another appliance.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 12-8.

 in the spam quarantine section, you can configure settings for access to the spam quarantine, and by default, HTTP uses port 82 and HTTPS uses port 83.

According to the [Cisco Secure Email Encryption Service Add-In User Guide], you can create an encryption profile that defines the encryption settings and options for your encrypted messages[2, p. 11]. You can also create an outgoing content filter that applies the encryption profile to the messages that match certain conditions, such as having [SECURE] in the subject header[2, p. 12]. This way, you can allow users to flag the messages that require encryption by adding [SECURE] to the subject line.

The other options are not valid because:

• A. Creating an encryption profile with [SECURE] in the Subject setting and enabling encryption on the mail flow policy will not work, as the Subject setting in the encryption profile is used to specify the subject line of the encrypted message envelope, not the original message[2, p. 11].
• B. Creating an outgoing content filter with no conditions and with the Encrypt and Deliver Now action configured with [SECURE] in the Subject setting will not work, as this will encrypt all outgoing messages regardless of whether they have [SECURE] in the subject line or not[2, p. 12].
• D. Creating a DLP policy manager message action with encryption enabled and applying it to active DLP policies for outgoing mail will not work, as this will encrypt messages based on DLP rules that detect sensitive data in the message content, not based on user flags in the subject line.

LDAP acceptance validation is a feature that allows the Cisco Secure Email Gateway to check if the recipient address of an incoming message exists in an LDAP directory before accepting it. This feature can help prevent spammers from sending emails with invalid recipient addresses and reduce the load on the appliance2. References = User Guide for AsyncOS 12.0 for Cisco Email Security Appliances - GD (General Deployment) - Configuring LDAP Queries [Cisco Secure Email Gateway] - Cisco

To allow phishing simul-ations to bypass antispam scanning, the administrator must add two components to the allow list: domains and senders. Domains are the email domains that are used in the phishing simulations, such as example.com or test.com. Senders are the email addresses that are used to send the phishing simulations, such as phish@example.com or test@test.com. By adding these components to the allow list, the administrator can prevent them from being blocked by antispam scanning and allow them to reach the end users for testing purposes. References: [Cisco Secure Email Gateway Administrator Guide - Creating Allow Lists]

ceo@example.com is the data that must be added to the dictionary to accomplish this goal. A content dictionary is a list of values that can be used as a condition in a content filter or a message filter. Forged Email Detection is a feature that allows Cisco ESA to detect and prevent email spoofing attacks, where the sender’s address or domain is forged to appear as someone else, such as the CEO of the organization.

To create a content dictionary for use with Forged Email Detection on Cisco ESA, the administrator can follow these steps:

• Select Mail Policies > Content Dictionaries and click Add Dictionary.
• Enter a name and description for the content dictionary, such as CEO Email.
• Under Dictionary Values, click Add Value.
• Enter the email address of the CEO, such as ceo@example.com.
• Click Submit.

The Outbreak Filters feature uses three tactics to protect your users from outbreaks:

Delay.

Redirect.

Modify.

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Load balancing and failover are two configurations that can be used on multiple LDAP servers to connect with Cisco ESA. Load balancing means that Cisco ESA will distribute the LDAP queries among the available LDAP servers in a round-robin fashion, improving the performance and efficiency of the LDAP queries. Failover means that Cisco ESA will switch to another LDAP server if the current one is unavailable or unresponsive, ensuring the continuity and reliability of the LDAP queries.

References: User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway, page 10-8.

You can enter multiple host names to configure the LDAP servers for failover or load-balancing. Separate multiple entries with commas.

Configuring DomainKeys and DKIM Signing:

-Signing Keys

-Public Keys

-Domain Profiles

Creating Domain Profiles:

Step 1

-Choose Mail Policies > Signing Profiles.

Step 2

-In the Domain Signing Profiles section, click Add Profile.

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To use the centralized spam quarantine on the Cisco Secure Email and Web Manager appliance, the administrator must disable the local spam quarantine on the Cisco Secure Email Gateway appliances. This will prevent messages from being stored in both quarantines and avoid confusion for end users and administrators. References: [Cisco Secure Email and Web Manager User Guide - Configuring Centralized Spam Quarantine]