sdn_sensor

SDN (Intel DPDK) based threat intelligence sensor in C99, with accompanying security event analytics stack in Java

Creator: Matthew Hall mhall@mhcomputing.net

Available under the MIT License.

Summary, aka tl;dr

The sdn_sensor is a user-mode security-aware TCP/IP network stack, which performs threat intelligence analysis of raw traffic, DNS packets, NetFlow / IPFIX, sFlow, and TCP and UDP Syslog protocols.

All traffic inspection results are processed using event correlation, aggregation, de-duplication, summarization, charting, reporting, and logging, as part of a high performance analytics stack, which is capable of handling 300,000 or more events per second, even in a laptop system.

The sdn_sensor is intended to help the security community bridge the gap between network hardware which can handle 10-100 gigabits/sec and 1,000,000 connections per second, and modern SIM (security information management) collectors and correlation systems, which usually only handle 100,000 logs per second in the best case, and cost $100,000 or more.

Up and Running With Vagrant

Get VirtualBox: VirtualBox Downloads.

Get vagrant: Vagrant Downloads.

1. vagrant up

2. vagrant ssh

3. cd /vagrant

4. Edit conf/sdn_sensor_vagrant.example. The Vagrant provisioning will copy it to sdn_sensor_vagrant.json and substitute some per-VM values into place. In particular the user should set {ipv4,ipv6}_{address,gateway}, log_level (if debugging), ioc_files / path.

5. Add some of your own threat intelligence to the ioc_file. The ioc_file CSV fields are:

    id (64-bit integer),type (ip, domain, url, email), threat_type / itype (free-form string), ip (optional), dns, ioc_value
   

6. cd src

7. make clean; make

8. sudo ../scripts/sdn_sensor.bash. (Use -d to load it in gdb.) Init and log messages from the sensor will appear on the console.

9. scripts/nn-receiver.pl will show the sensor logs. They are JSON-format messages routed through nanomsg, which is a native C, Berkeley Socket like MQ library based upon, and simplified from, ZeroMQ. nanomsg has many language bindings, including a Java language binding, which is used by the included analytics stack to receive messages from the sdn_sensor core.

10. scripts/sloccount.bash will show the lines of code and US-dollar value and time / schedule needed to develop all of the code.

Design Philosophy

The sdn_sensor is designed around the assumption that every large network already contains malicious traffic, compromised systems, malware, and APT's (Advanced Persistent Threats). Usually these arrive via diverse sources, such as email, mobile devices, BYOD (bring your own device), open / share network resources (such as SAN's, file sharing, etc.), user error, software defects, etc.

Even the US SEC (United States Securities and Exchange Commission) has adopted this assumption. Since 2011, the SEC requires publicly-traded US corporations to report their cybersecurity risks which could have a material impact on their securities.

In the face of this new reality we are all trying to figure out what to do! It seems somewhat pointless to try to filter the traffic for specific exploits or signatures, or to assume firewall or IPS rules will actually prevent much of anything.

Instead, the sdn_sensor is based on the idea that it makes more sense to try to detect the activity that is surely already happening rather than prevent the apparently unpreventable. To accomplish this, several knowledge sources and technologies are combined in a single codebase:

• Threat Intelligence IOC's (Indicators of Compromise), such as known malicious IP's, DNS Domains, URL's, Email Addresses, and File Hashes,
• SDN-based (software defined networking) user-space packet processing, which allows many gigabits per second of traffic or management metadata to be inspected at line rate, based on Intel DPDK (Data Plane Development Kit),
• high-bandwidth low-latency message queuing, used for years in stock markets and other major world financial transaction processing systems,
• low-latency in-memory streaming database, ESP (event stream processing), and CEP (complex event processing) engines, designed to dig through huge volumes of event haystacks to find the needles of valuable data, originally used in HFT (high-frequency trading in financial markets)

The sdn_sensor leverages the talents and achievements of these communities:

• the intelligence community,
• the information security community,
• the network hardware community,
• the financial markets community.

By integrating the amazing things these communities have created, the sdn_sensor can successfully detect malicious activities already in progress, and allow monitoring, incident response, and remediation as issues arise, even in the face of the numerous technical challenges.

Technical Details

IOC matching in the sdn_sensor is performed against the following areas:

• packet headers from IPv4, IPv6, TCP, and UDP,
• DNS question and answer contents,
• flow records from NetFlow, IPFIX, or sFlow,
• UDP and TCP based Syslog (an O(n) regex engine is used to extract tokens which appear to be IOCs from inside the text of the log messages).

In addition to these, it is possible to perform matching with:

• libpcap filter expressions,
• CIDR blocks in IPv4 or IPv6,
• DNS names or IP's inside DNS questions and answers.

Coding Standards

1. Use 4 spaces for all indent levels.

2. Don't bother with 80-character lines, just make it readable.

3. The "standard name prefix" for functions / globals is "ss_" (short for sdn_sensor).

4. Lots of compiler warnings are on by default. The clang scan-build tool will find even more bugs.

5. Don't use messy or complicated code that is hard to debug.

6. Mark any questionable, hacked, known-buggy or otherwise suspect code with XXX so other people can find it and fix it. It doesn't have to be perfect right away but don't lie to the person who comes after you.

7. Use a lot of log messages as this is young software with bugs.

8. Put filename: one-line description on every git commit message.

9. Use well known best-in-class dependency libraries. Follow the principle of least surprise as much as possible. Try to make git submodules for the dependencies so it's easy to track and update them.

10. Allocate all memory using DPDK or libjemalloc. Don't use the libc allocator, because it is way too slow and buggy. Remember many string.h functions call libc alloc secretly. This will cause segfaults if pointers get mixed between libjemalloc and libc. To avoid this re-implement any broken string functions in je_utils.c.

11. Use the make cproto command to auto-update the function prototypes, it makes life easy. Use scripts/create-header-file.pl to make new blank header files in the right format to work with make cproto.

SECURITY NOTICES

THIS IS ALPHA CODE, WITH BASIC QA TESTING ONLY!!!

WARNING: DPDK more or less directly or indirectly allows the code to read and write any arbitrary addresses in system memory whatsoever without any restrictions.

Fundamentally DPDK allows Bus Master and DMA (direct memory access) by the NIC (network interface card) by design. This means that PCIe (PCI Express) bus on the motherboard permits almost unlimited read and write access to all of system memory, user-space or kernel-space, or any other region(s) present.

Some effort is taken to ensure no obvious vulnerabilities are present using Coverity, but this is early code, and it has a ton of complex network stack logic, using raw C pointer manipulation. Definitely don't try to run this on any sensitive or trusted machines.

With virtualization it is safer, as it should only be able to take over the VM, and not the hypervisor. However if you use native PCI Passthrough, or other raw or low level VF (Virtual Functions) on the NIC's, or special DPDK Ethernet drivers, anything could happen. Think carefully.

Coverity Scan Static Analysis Results