Category Archives: Azure

This blog post was co-authored by Aditya Joshi, Senior Software Engineer, Enterprise Protection and Detection.

Attackers are increasingly employing stealthier methods to avoid detection. Fileless attacks exploit software vulnerabilities, inject malicious payloads into benign system processes, and hide in memory. These techniques minimize or eliminate traces of malware on disk, and greatly reduce the chances of detection by disk-based malware scanning solutions.

To counter this threat, Azure Security Center released fileless attack detection for Windows in October 2018. Our blog post from 2018 explains how Security Center can detect shellcode, code injection, payload obfuscation techniques, and other fileless attack behaviors on Windows. Our research indicates the rise of fileless attacks on Linux workloads as well.

Today, Azure Security Center is happy to announce a preview for detecting fileless attacks on Linux.  In this post, we will describe a real-world fileless attack on Linux, introduce our fileless attack detection capabilities, and provide instructions for onboarding to the preview. 

Real-world fileless attack on Linux

One common pattern we see is attackers injecting payloads from packed malware on disk into memory and deleting the original malicious file from the disk. Here is a recent example:

1. An attacker infects a Hadoop cluster by identifying the service running on a well-known port (8088) and uses Hadoop YARN unauthenticated remote command execution support to achieve runtime access on the machine. Note, the owner of the subscription could have mitigated this stage of the attack by configuring Security Center JIT.
2. The attacker copies a file containing packed malware into a temp directory and launches it.
3. The malicious process unpacks the file using shellcode to allocate a new dynamic executable region of memory in the process’s own memory space and injects an executable payload into the new memory region.
4. The malware then transfers execution to the injected ELF entry point.
5. The malicious process deletes the original packed malware from disk to cover its tracks. 
6. The injected ELF payload contains a shellcode that listens for incoming TCP connections, transmitting the attacker’s instructions.

This attack is difficult for scanners to detect. The payload is hidden behind layers of obfuscation and only present on disk for a short time.  With the fileless attack detection preview, Security Center can now identify these kinds of payloads in memory and inform users of the payload’s capabilities.

Fileless attacks detection capabilities

Like fileless attack detection for Windows, this feature scans the memory of all processes for evidence of fileless toolkits, techniques and behaviors. Over the course of the preview, we will be enabling and refining our analytics to detect the following behaviors of userland malware:

• Well known toolkits and crypto mining software. 
• Shellcode, injected ELF executables, and malicious code in executable regions of process memory.
• LD_PRELOAD based rootkits to preload malicious libraries.
• Elevation of privilege of a process from non-root to root.
• Remote control of another process using ptrace.

In the event of a detection, you receive an alert in the Security alerts page. Alerts contain supplemental information such as the kind of techniques used, process metadata, and network activity. This enables analysts to have a greater understanding of the nature of the malware, differentiate between different attacks, and make more informed decisions when choosing remediation steps.

The scan is non-invasive and does not affect the other processes on the system.  The vast majority of scans run in less than five seconds. The privacy of your data is protected throughout this procedure as all memory analysis is performed on the host itself. Scan results contain only security-relevant metadata and details of suspicious payloads.

Getting started

To sign-up for this specific preview, or our ongoing preview program, indicate your interest in the “Fileless attack detection preview.”

Once you choose to onboard, this feature is automatically deployed to your Linux machines as an extension to Log Analytics Agent for Linux (also known as OMS Agent), which supports the Linux OS distributions described in this documentation. This solution supports Azure, cross-cloud and on-premise environments. Participants must be enrolled in the Standard or Standard Trial pricing tier to benefit from this feature.

To learn more about Azure Security Center, visit the Azure Security Center page.

This post was co-authored by Suren Jamiyanaa, Program Manager, Azure Networking

We continue to be amazed by the adoption, interest, positive feedback, and the breadth of use cases customers are finding for our service. Today, we are excited to share several new Azure Firewall capabilities based on your top feedback items:

• ICSA Labs Corporate Firewall Certification.
• Forced tunneling support now in preview.
• IP Groups now in preview.
• Customer configured SNAT private IP address ranges now generally available.
• High ports restriction relaxation now generally available.

Azure Firewall is a cloud native firewall as a service (FWaaS) offering that allows you to centrally govern and log all your traffic flows using a DevOps approach. The service supports both application and network level filtering rules and is integrated with the Microsoft Threat Intelligence feed for filtering known malicious IP addresses and domains. Azure Firewall is highly available with built-in auto scaling.

ICSA Labs Corporate Firewall Certification

ICSA Labs is a leading vendor in third-party testing and certification of security and health IT products, as well as network-connected devices. They measure product compliance, reliability, and performance for most of the world’s top technology vendors.

Azure Firewall is the first cloud firewall service to attain the ICSA Labs Corporate Firewall Certification. For the Azure Firewall certification report, see information here. For more information, see the ICSA Labs Firewall Certification program page.

Figure one – Azure Firewall now ICSA Labs certified.

Forced tunneling support now in preview

Forced tunneling lets you redirect all internet bound traffic from Azure Firewall to your on-premises firewall or a nearby Network Virtual Appliance (NVA) for additional inspection. By default, forced tunneling isn’t allowed on Azure Firewall to ensure all its outbound Azure dependencies are met.

To support forced tunneling, service management traffic is separated from customer traffic. An additional dedicated subnet named AzureFirewallManagementSubnet is required with its own associated public IP address. The only route allowed on this subnet is a default route to the internet, and BGP route propagation must be disabled.

Within this configuration, the AzureFirewallSubnet can now include routes to any on-premise firewall or NVA to process traffic before it’s passed to the Internet. You can also publish these routes via BGP to AzureFirewallSubnet if BGP route propagation is enabled on this subnet. For more information see Azure Firewall forced tunneling documentation.

Figure two – Creating a firewall with forced tunneling enabled.

IP Groups now in preview

IP Groups is a new top-level Azure resource in that allows you to group and manage IP addresses in Azure Firewall rules. You can give your IP group a name and create one by entering IP addresses or uploading a file. IP Groups eases your management experience and reduce time spent managing IP addresses by using them in a single firewall or across multiple firewalls. For more information, see the IP Groups in Azure Firewall documentation.

Figure three – Azure Firewall application rules utilize an IP group.

Customer configured SNAT private IP address ranges

Azure firewall provides automatic Source Network Address Translation (SNAT) for all outbound traffic to public IP addresses. Azure Firewall doesn’t SNAT when the destination IP address is a private IP address range per IANA RFC 1918. If your organization uses a public IP address range for private networks or opts to force tunnel Azure Firewall internet traffic via an on-premises firewall, you can configure Azure Firewall to not SNAT additional custom IP address ranges. For more information, see Azure Firewall SNAT private IP address ranges.

Figure four – Azure Firewall with custom private IP address ranges.

High ports restriction relaxation now generally available

Since its initial preview release, Azure Firewall had a limitation that prevented network and application rules from including source or destination ports above 64,000. This default behavior blocked RPC based scenarios and specifically Active Directory synchronization. With this new update, customers can use any port in the 1-65535 range in network and application rules.

Next steps

For more information on everything we covered above please see the following blogs, documentation, and videos.

• Azure Firewall documentation.
• Azure Firewall July 2019 blog: What’s new in Azure Firewall.
• Azure Firewall Manager documentation.
• Azure Firewall Manager blog: Azure Firewall Manager now supports virtual networks.

Azure Firewall central management partners:

• AlgoSec CloudFlow.
• Barracuda Cloud Security Guardian, now generally available in Azure Market.
• Tufin SecureCloud.

This post was co-authored by Yair Tor, Principal Program Manager, Azure Networking.

Last November we introduced Microsoft Azure Firewall Manager preview for Azure Firewall policy and route management in secured virtual hubs. This also included integration with key Security as a Service partners, Zscaler, iboss, and soon Check Point. These partners support branch to internet and virtual network to internet scenarios.

Today, we are extending Azure Firewall Manager preview to include automatic deployment and central security policy management for Azure Firewall in hub virtual networks.

Azure Firewall Manager preview is a network security management service that provides central security policy and route management for cloud-based security perimeters. It makes it easy for enterprise IT teams to centrally define network and application-level rules for traffic filtering across multiple Azure Firewall instances that spans different Azure regions and subscriptions in hub-and-spoke architectures for traffic governance and protection. In addition, it empowers DevOps for better agility with derived local firewall security policies that are implemented across organizations.

For more information see Azure Firewall Manager documentation.

Figure one – Azure Firewall Manger Getting Started page

Hub virtual networks and secured virtual hubs

Azure Firewall Manager can provide security management for two network architecture types:

•  Secured virtual hub—An Azure Virtual WAN Hub is a Microsoft-managed resource that lets you easily create hub-and-spoke architectures. When security and routing policies are associated with such a hub, it is referred to as a secured virtual hub.

•  Hub virtual network—This is a standard Azure Virtual Network that you create and manage yourself. When security policies are associated with such a hub, it is referred to as a hub virtual network. At this time, only Azure Firewall Policy is supported. You can peer spoke virtual networks that contain your workload servers and services. It is also possible to manage firewalls in standalone virtual networks that are not peered to any spoke.

Whether to use a hub virtual network or a secured virtual depends on your scenario:

•  Hub virtual network—Hub virtual networks are probably the right choice if your network architecture is based on virtual networks only, requires multiple hubs per regions, or doesn’t use hub-and-spoke at all.

•  Secured virtual hubs—Secured virtual hubs might address your needs better if you need to manage routing and security policies across many globally distributed secured hubs. Secure virtual hubs have high scale VPN connectivity, SDWAN support, and third-party Security as Service integration. You can use Azure to secure your Internet edge for both on-premises and cloud resources.

The following comparison table in Figure 2 can assist in making an informed decision:

Figure 2 – Hub virtual network vs. secured virtual hub

Firewall policy

Firewall policy is an Azure resource that contains network address translation (NAT), network, and application rule collections as well as threat intelligence settings. It’s a global resource that can be used across multiple Azure Firewall instances in secured virtual hubs and hub virtual networks. New policies can be created from scratch or inherited from existing policies. Inheritance allows DevOps to create local firewall policies on top of organization mandated base policy. Policies work across regions and subscriptions.

Azure Firewall Manager orchestrates Firewall policy creation and association. However, a policy can also be created and managed via REST API, templates, Azure PowerShell, and CLI.

Once a policy is created, it can be associated with a firewall in a Virtual WAN Hub (aka secured virtual hub) or a firewall in a virtual network (aka hub virtual network).

Firewall Policies are billed based on firewall associations. A policy with zero or one firewall association is free of charge. A policy with multiple firewall associations is billed at a fixed rate.

For more information, see Azure Firewall Manager pricing.

The following table compares the new firewall policies with the existing firewall rules:

Figure 3 – Firewall Policy vs. Firewall Rules

Next steps

For more information on topics covered here, see the following blogs, documentation, and videos:

•  Azure Firewall Manager documentation
•  Azure Firewall Manager Pricing

Azure Firewall central management partners:

• AlgoSec CloudFlow
• Barracuda Cloud Security Guardian, now generally available in Azure Market
• Tufin SecureCloud