Palo Alto Networks NDM Security Technical Implementation Guide

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced.

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. By default, the Configuration Log contains the administrator username, client (Web or CLI), and date and time for any changes to configurations and for configuration commit actions. The System Log also shows both successful and unsuccessful attempts for configuration commit actions. The System Log and Configuration Log can be configured to send log messages by severity level to specific destinations; the Panorama management console, an SNMP console, an e-mail server, or a syslog server. Since both the System Log and Configuration Log contain information concerning the use of privileges, both must be configured to send messages to a syslog server at a minimum.

In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable unused or unnecessary physical and logical ports/protocols on information systems. Network devices are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., email and web services); however, doing so increases risk over limiting the services provided by any one component. To support the requirements and principles of least functionality, the network device must support the organizational requirements providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues. The Palo Alto Networks security platform uses a hardened operating system in which unnecessary services are not present. The device has a DNS, NTP, update, and e-mail client installed. Note that these are client applications and not servers; additionally, each has a valid purpose. However, local policy may dictate that the update service, e-mail client, and statistics (reporting) service capabilities not be used. DNS can be either "Server" or "Proxy"; both are allowed unless local policy declares otherwise. NTP and SNMP are necessary functions.

To assure accountability and prevent unauthenticated access, organizational administrators must be uniquely identified and authenticated for all network management accesses to prevent potential misuse and compromise of the system.

A replay attack may enable an unauthorized user to gain access to the application. Authentication sessions between the authenticator and the application validating the user credentials must not be vulnerable to a replay attack. An authentication process resists replay attacks if it is impractical to achieve a successful authentication by recording and replaying a previous authentication message. Techniques used to address this include protocols using nonces (e.g., numbers generated for a specific one-time use) or challenges (e.g., TLS, WS_Security). Additional techniques include time-synchronous or challenge-response one-time authenticators. Of the three authentication protocols on the Palo Alto Networks security platform, only Kerberos is inherently replay-resistant. If LDAP is selected, TLS must also be used. If RADIUS is used, the device must be operating in FIPS mode.

Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. The shorter the password, the lower the number of possible combinations that needs to be tested before the password is compromised. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

Use of a complex passwords helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password is, the greater the number of possible combinations that needs to be tested before the password is compromised.

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that needs to be tested before the password is compromised.

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that needs to be tested before the password is compromised.

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that needs to be tested before the password is compromised.

If the application allows the user to consecutively reuse extensive portions of passwords, this increases the chances of password compromise by increasing the window of opportunity for attempts at guessing and brute-force attacks. The number of changed characters refers to the number of changes required with respect to the total number of positions in the current password. In other words, characters may be the same within the two passwords; however, the positions of the like characters must be different.

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Network devices can accomplish this by making direct function calls to encryption modules or by leveraging operating system encryption capabilities.

The Palo Alto Networks security platform has both pre-configured and configurable Administrator roles. Administrator roles determine the functions that the administrator is permitted to perform after logging in. Roles can be assigned directly to an administrator account, or define role profiles, which specify detailed privileges, and assign those to administrator accounts. There are three preconfigured roles designed to comply with Common Criteria requirements - Security Administrator, Audit Administrator, and Cryptographic Administrator. Of the three, only the Audit Administrator can delete audit records. The Palo Alto Networks security platform can use both pre-configured and configurable Administrator roles.

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account. This should not be configured in Device >> Setup >> Management >> Authentication Settings; instead, an authentication profile should be configured with lockout settings of three failed attempts and a lockout time of zero minutes. The Lockout Time is the number of minutes that a user is locked out if the number of failed attempts is reached (0-60 minutes, default 0). 0 means that the lockout is in effect until it is manually unlocked.

The loss of connectivity to a particular authoritative time source will result in the loss of time synchronization (free-run mode) and increasingly inaccurate time stamps on audit events and other functions. Multiple time sources provide redundancy by including a secondary source. Time synchronization is usually a hierarchy; clients synchronize time to a local source while that source synchronizes its time to a more accurate source. DOD-approved solutions consist of a combination of a primary and secondary time source using a combination or multiple instances of the following: a time server designated for the appropriate DOD network (NIPRNet/SIPRNet); United States Naval Observatory (USNO) time servers; and/or the Global Positioning System (GPS). The secondary time source must be located in a different geographic region from the primary time source.

If time stamps are not consistently applied and there is no common time reference, it is difficult to perform forensic analysis. Time stamps generated by the application include date and time and must be expressed in Coordinated Universal Time (UTC), also known as Zulu time, a modern continuation of Greenwich Mean Time (GMT).

The use of PIV credentials facilitates standardization and reduces the risk of unauthorized access. DOD has mandated the use of the CAC to support identity management and personal authentication for systems covered under HSPD 12 and as a primary component of layered protection for national security systems.

This requires the use of secure protocols instead of their unsecured counterparts, such as SSH instead of telnet, SCP instead of FTP, and HTTPS instead of HTTP. Note that HTTP OCSP is permitted to support OCSP where used. If unsecured protocols (lacking cryptographic mechanisms) are used for sessions, the contents of those sessions will be susceptible to manipulation, potentially allowing alteration and hijacking of maintenance sessions.

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity. The Palo Alto Networks security platform has multiple log types; at a minimum, the Traffic, Threat, System, and Configuration logs must be sent to a Syslog server.

CJCSM 6510.01B, "Cyber Incident Handling Program", in subsection e.(6)(c) sets forth three requirements for Cyber events detected by an automated system: If the cyber event is detected by an automated system, an alert will be sent to the POC designated for receiving such automated alerts. CC/S/A/FAs that maintain automated detection systems and sensors must ensure that a POC for receiving the alerts has been defined and that the IS configured to send alerts to that POC. The POC must then ensure that the cyber event is reviewed as part of the preliminary analysis phase and reported to the appropriate individuals if it meets the criteria for a reportable cyber event or incident. By immediately displaying an alarm message, potential security violations can be identified more quickly even when administrators are not logged on to the network device. An example of a mechanism to facilitate this would be through the utilization of SNMP traps. The Palo Alto Networks security platform can be configured to send messages to an SNMP server and to an email server as well as a Syslog server. SNMP traps can be generated for each of the five logging event types on the firewall: traffic, threat, system, hip, config. For this requirement, only the threat logs must be sent. Note that only traffic that matches an action in a rule will be logged and forwarded. In the case of traps, the messages are initiated by the firewall and sent unsolicited to the management stations. The use of email as a notification method may result in a very larger number of messages being sent and possibly overwhelming the email server as well as the POC. The use of SNMP is preferred over email in general, but organizations may want to use email in addition to SNMP for high-priority messages.

The use of authentication servers or other centralized management servers for providing centralized authentication services is required for network device management. Maintaining local administrator accounts for daily usage on each network device without centralized management is not scalable or feasible. Without centralized management, it is likely that credentials for some network devices will be forgotten, leading to delays in administration, which itself leads to delays in remediating production problems and in addressing compromises in a timely fashion. Only the emergency administration account, also known as the account of last resort, can be locally configured on the device.

DoD Instruction 8520.02, Public Key Infrastructure (PKI) and Public Key (PK) Enabling mandates that certificates must be issued by the DoD PKI or by a DoD-approved PKI for authentication, digital signature, or encryption.

Password profiles override settings made in the Minimum Password Complexity window. If Password Profiles are used they can bypass password complexity requirements.

Auditing and logging are key components of any security architecture. Logging the actions of specific events provides a means to investigate an attack; to recognize resource utilization or capacity thresholds; or to identify an improperly configured network device. If auditing is not comprehensive, it will not be useful for intrusion monitoring, security investigations, and forensic analysis. If the Data Plane CPU utilization is 100%, this may indicate an attack or simply an over-utilized device. In either case, action must be taken to identify the source of the issue and take corrective action.

If Network Time Protocol is not authenticated, an attacker can introduce a rogue NTP server. This rogue server can then be used to send incorrect time information to network devices, which will make log timestamps inaccurate and affected scheduled actions. NTP authentication is used to prevent this tampering by authenticating the time source.

Authentication for administrative (privileged level) access to the device is required at all times. An account can be created on the device's local database for use when the authentication server is down or connectivity between the device and the authentication server is not operable. This account is referred to as the account of last resort since it is intended to be used as a last resort and when immediate administrative access is absolutely necessary. The account of last resort logon credentials must be stored in a sealed envelope and kept in a safe. The safe must be periodically audited to verify the envelope remains sealed. The signature of the auditor and the date of the audit should be added to the envelope as a record. Administrators should secure the credentials and disable the root account (if possible) when not needed for system administration functions.