Network Security

The Importance of Retrospective Network Security

Network Security

We are experiencing a new phase in our vision of network security. There is currently no quick fix solution, no 100% proof network security protection/prevention tool or product. There is always zero-day or purposely built (very focused, low spread) APT malware that current vendors are unable to detect at the time of the breach.

Hence total prevention is a myth.

Most of the current network security solutions offer only Point-In-Time detection/prevention. Namely they inspect the traffic when the traffic goes via the firewall and if they deem the traffic is clean  or unknown, at that exact time, they will allow it and forget about it. That could lead to malware passing through and being undetected for long periods of time. All vendors rely on intercepting the C&C communication to the botnet servers but not all malware uses such a centralized operation method so that cannot be considered a proven method of detection. That is why most of the vendors will apply their own sandboxing solution, namely send all files of unknown malware type to the cloud where they will be detonated in a controlled environment and the result of their execution will be deemed malicious or not by machines or sometimes humans. Upon discovery of malicious actions, the file is marked as malware and an update is shot out to all vendor appliances out there so they can intercept and drop such files. That process however takes time (typically more than 8 hours) and usually stops more than 96% of the malware spread (it depends on how quickly the different vendors discover that the file is malicious and how quickly the update is sent out) and that percentage was deemed high-enough for most companies.

What about that 4% though? I am sure any business owner would not like to be in this position and would like greater protection and value for their money. When a mere 4% can cause 100% of your security problems, you’re not protected.

Cisco is the only vendor in the NGFW market that currently has its vision also set on the retrospective side of the network security, the so-called After-The-Attack phase. Cisco uses the combination between Firepower and AMP for both network and endpoint to be able to provide threat context and to pinpoint the progress and spread of the malware in historical time so you will know exactly when and how the malware moved in your network, which hosts were infected so that you can immediately deploy mitigation techniques. First restrict the malware, block the effect of the malware and finally remove the malware that has already breached your network. Without this continuous analysis, the attack can run rampant on the network and it will be extremely difficult to determine the scope of the outbreak and the root cause or provide on-time/adequate response. Here is an example of such an event and how Firepower and AMP deal with it.

The following 4 simple steps represent how Firepower and Amp works with zero-day malware files:

  1. Unknown file gets downloaded to a client ip (1.2.3.4 for example) via http application with Firefox, the file is then allowed to reach the endpoint. The unknown file is sent to the cloud to be detonated and given a verdict.
  2. The Firepower tracks the movement/copying of the file within the network so it sees the file being propagated via any protocol at any time. For example, the file gets copied to another host 1.2.3.5 via SMB at 12:41 AM on the 1st of Dec 2016.
  3. Within 30min the same file gets replicated to 5 more devices within the internal range, all via SMB. The Firepower has a map of the file trajectory with hosts and timing of the movements.
  4. Two hours since the file was first seen, Cisco Security Intelligence Cloud had reached a verdict that the file in question is in fact malicious. From now on all Cisco AMP and Firepower enabled devices will drop that file upon encounter and alarm/log, but here comes the difference between Cisco and other vendors, namely the retrospective part. In our example, all future transfer of the files will be blocked and the file itself will be quarantined on all endpoints that have this file (requires AMP for endpoint), even more the administrators can leverage the trajectory map and verify the malicious file has been quarantined/removed and hosts have been remediated.

Abbreviations:

APT – Advanced Persistent Threats

C&C – Command and Control

NGFW – Next-Generation Firewall

Network Security, Cyber Security

8 Steps to Secure Your Organization against Cyber-Attacks

Network Security, Cyber Security

There is not a single industry anywhere in the world who are immune from the threat of some form of cyber-attack. Any attacks on your organization’s IT Network will be unpredictable in terms of the exact method of attack, but you can at least be poised to deflect and protect your company from such cyber-attacks with these 8 easy to follow steps.

1. Implement your CyberSecurity strategy from the top-down

Devise a security strategy, make sure Directors and Management understand the importance of your organization’s IT Network Security. The fundamental thing about security is knowing the risks involved and understanding what needs to be secured, namely what are your valuables/assets.

Only after a thorough risk assessment has been carried out can a proper security strategy then be formed and implemented. The importance of cyber-security should be something that senior management understands and supports, resulting in a top-down approach to implementation.

2. Create polices for the allocation of internal IT Resources

Once the importance of security issues is fully understood by management, organizations can then begin to create and implement polices on how to use, manage and allocate company resources to tackle cyber security.

It is vital to then develop and enforce policies and procedures for employees to follow, this will impact:

  • The allocation of company IT resources – allowed and prohibited expenditure
  • Change management procedures to be implemented across all IT systems and related policies
  • Reevaluate risk and security posture at regular intervals

3. Network Security

Have a network design with a strong focus on cyber-security. Segment your network on logical system based zones so you can isolate/segregate critical business systems and be able to apply network security controls to them – firewall/inspect traffic between those zones. Protect your Internet Edge but also internal traffic (east-west), cover the most used vectors of attack (email, web)

Pay special attention to wireless connectivity – use strong authentication based on individual credentials or personal certificates, strong encryption (AES) and proper guest/BYOD access. Plan carefully, home and remote users access – they should have equal security controls as users on corporate networks.

Have a central point for system monitoring (SIEM) that is integrated within your environment and provides a single point that holds all relative logs/events for your systems. Monitor your network/user activity with qualified staff. Fine tune your IPS systems to use relative to your network environment security rules/signatures and to produce relevant alarms. Act on the alarms promptly.

Secure both user/management and physical access to your network assets. Apply only secure configuration using the vendor/standard recommended best practices. Have a lifecycle policy in place – aka review/renew security controls/equipment at regular intervals. Finally, ensure you have an up to date network diagram with HLD/LLD documents.

4. Protect your endpoints/servers

Always use legitimately supported software and hardware. Create and maintain a policy for patching and updates – keep up to date with patches and security updates.

Devise and maintain a hardware and software repository – know what you have in your network. Centrally manage your endpoint from OS and software point of view. Limit user rights to make changes to endpoint security:

  • Never give normal users full access (admin)
  • Limit execution controls/change configuration
  • Create safe-lists of allowed software
  • Disable unnecessary services
  • Disable unnecessary peripheral devices and removable media access
  • Disable auto-run capability if removable media access is deemed necessary

Accessing sensitive information should be done in a secure manner – proper access controls should be in place – secure and robust authentication mechanisms, use two-factor authentication for sensitive access, encryption for data in transit and rest. Monitoring of how sensitive data is handled and transferred should also be in place.

Use endpoint protection mechanism (Anti-Virus, Anti-Spyware, Software, Firewalls) which support centralised management and can be integrated with your network security controls and monitoring tools. Regularly backup all important data in a safe manner (encrypt and secure data in rest in motion) – this mitigates the effects of ransomware attacks. In case of a breach, have a plan to restore normal network operations for different scenarios but also remember to include steps for gathering data for forensic investigations to take place in the aftermath.

5. Train your personnel

Users should be aware of the ideas behind the implementation of security

measures, what threats are out there and what should raise their suspicion – simple things like:

  • Non-solicited mails with strange hidden links – aka “Think before you click campaign”
  • File attachment with general but well-sounding names
  • Plugging/connecting unapproved media or personal devices into the network

Users should undergo training on:

  • How to handle sensitive information
  • Social Engineering training and be aware of the techniques used
  • Report any strange activities or security incidents

The training and development of personnel should be a continuous process not a one-off occurrence to ensure topics are relevant, minimise any potential threats and so staff training can be scaled.

6. Remote/Home Users controls

Access risks for remote corporate users and create a policy on how to mitigate their usage. Use strong/two-factor authentication. Educate remote users on the importance of security and how to work with all security control mechanisms without sacrificing productivity.

Create and regularly update manuals on how to use and configure different security controls (aka VPN Clients etc.) Have a support and escalation procedure in place – this is done so users can work with all security controls in place and do not try to circumvent them. Protect data in transit and rest. Use a common security build for all remote workers – more secure, easier to operate and troubleshoot.

7. Monitoring

We cannot stress enough on the importance of constant monitoring. No environment is bullet proof and buying best of breed products does not guarantee top level of security. There is a lot of factors in play in every complex environment that has many cogs and bolts. The only predictable aspect about security is the unpredictability of the threats they pose (for example the human factor or administrator laziness). A link as strong as its weakest chain. A company should concentrate on having all protection/prevention mechanisms in place but should never forget to have visibility and monitoring tools in place.

Detect attacks and abnormal behaviour – both from outside and inside attacks. React to attacks – in a timely response to stop the spread of damage, can ensure that the attack is blocked in the future and could assist with a forensic investigation. Account for activity – you should have a complete understanding of how systems run, and how data and information is being used by users. Only then will you be able to detect deviations from the norm and act on them.

8. Test, test and test!

The only way to really know your security level is protecting your organization, is to regularly test it!

Security tests should cover all parts of your environment and should be performed on procedures/processes, network equipment, endpoint systems and personnel.

  • Formal security audits that look at procedures and if they are being followed/enforced
  • Automated vulnerability assessments – usually performed every 2-3 months and done internally
  • Penetration tests – external annual security tests that usually give the most accurate information for the company’s security posture and effectiveness of all security measures deployed
  • Social engineering tests on personnel – attempts to get employees to discard sensitive information to none-authorised people either via phone or in person or to get physical access to company restricted areas.

Jargon Buster

  1. HLD – High Level Design
  2. LLD – Low Level Design
  3. IT – Information Technology
  4. IPS – Intrusion Prevention System
  5. SIEM – combination of the SIM (Security Information Management) and SEM (Security Event Management) abbreviations
  6. OS – Operating System
  7. AES – Advanced Encryption Standard
  8. BYOD – Bring Your Own Device
  9. Social Engineering – a method in Penetration Testing when the security experts are trying to exploit the human personality into giving out sensitive information that could lead to a breach in security

References:

https://www.ncsc.gov.uk/guidance/10-steps-cyber-security https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/317481/Cyber_Essentials_Requirements.pdf

Cisco Security

Why do legacy ASAs need Migration to ASA X Generation?

Cisco Security

The traditional legacy ASA Firewalls (5505, 5510, 5520, 5540, 5580) are End of Life (EOL) and soon will be End of Support (EOS). There are still a vast number of ASA’s in the public realm used as a security device/internet edge firewalls where many companies think they are providing the necessary security, the reality cannot be further from the truth.

These older model ASA’s have the following problems

  1. Hardware Problems

Cisco ASA Firewalls have a Meantime-Between-Failure (MTBF) which is simply the predicted elapsed time between inherent failures of such devices. When legacy ASA’s are out of support it is not possible to renew support contracts as Firmware updates are no longer available, effectively making the devices EOL. Meaning they are a ticking bomb and without support any network can suffer significant downtime when the device gives up.

  1. Code Vulnerabilities

ASA updates are uncommon, occurring every 6 months or so, meaning security holes can appear with such a time gap between security patch updates. Effectively your device is vulnerable and unsecured whilst it awaits the next patch update. Currently legacy ASA Firewalls only run to version 9.1 updates. These vulnerability problems wouldn’t be a threat if default and most deployed scenario is an Internet Edge Firewall.

  1. Lack of new features

Cisco is not deploying any new features to the legacy ASA’s and the major version will probably not move away from 9.1 (when the newest is 9.6 for next generation Firewalls)

  1. Lack of real security

Any working firewall cannot only rely on the Stateful Firewall technology for protecting the assets of an organization. Legacy ASA’s can only run the legacy Cisco IPS with a separate module which cannot measure to the modern IPS technology. The new generation of firewalls have the Firepower functionality which is the industry leading IPS technology.

Challenges for migrating Legacy ASA to ASA X?

  1. Configuration migration
  • Manual migration – Configuration between Legacy ASA’s and the new ASA X usually differs and cannot be simply copied and pasted into the new device. Different naming for interfaces and different features and functionalities means different syntax for the CLI.

Very often the legacy ASA’s run a pre-8.3 code due to RAM restrictions (RAM needs to be upgraded for post 8.3+ code). The pre-8.3 code is very different from today’s code in terms of syntax. It does mandate the obligatory use of objects, the NATs are the old PIX like fashion and any policies use the global ip addresses (the so called real ip addresses seen on the interface) than the original one (the ip addresses on the hosts). That means that large portions of the config need to be redone (in most cases manually) when you do the switch over.

The sections that needs manual work are: Objects, NATs, Policies and ACLs. That is the recommended approach and usually an experienced Cisco Security Consultant is needed to perform the job.

  • Automatic migration is possible if the legacy ASA has its RAM upgraded (512MB for 5505 and more than 1GB for the other models is mandatory). Depending on the starting OS Image version several upgrades are done to ensure the device runs the latest 8.2.x code and then jump to 8.4.1. During that jump the device will automatically redo the configuration to its best (will shout out errors on console while booting if it cannot migrate certain areas of the config), it will create objects (with automatic names) and will deploy them.

During automatic migrations, there is always a chance that something will not work so the migration again needs to be performed by someone who understands the migration process, can track down and manually intervene to correct errors or add configuration after the migration. Also, the configuration after an automatic migration is not easily readable due to the creation of objects with automatic naming convention.

  • Raising the security level – if you migrated from a legacy ASA to a new generation ASA X that supports other security technologies and Firepower then it makes sense to leverage new technologies and enable/configure/tune them. A blind one-to-one migration might give you more in the world of availability (new hardware, newer code, less code vulnerabilities and frequent code updates), but will not give you ultimately better protection for your assets. A deep packet inspection with content analysis is a must in the modern threat landscape. Implementing the Firepower technology is necessary but a complex step that needs to be done by people with the right skillset and experience.

References:

  1. EOS / EOL announcement

http://www.cisco.com/c/en/us/products/collateral/security/asa-5500-series-next-generation-firewalls/eol_C51-727283.html