Skip to content

Second look


Forcepoint Linux Security (Second Look) is a Linux security product that performs Memory Integrity scans. It uses memory forensics and integrity verification to report on the state of a system and to alert on unknown and potentially malicious code in memory. It is designed for two use cases: 1. intrusion detection (early warning system for Linux compromise), and 2. incident response (memory acquisition and analysis for forensic investigation).


Second Look began at Pikewerks Corporation. The original R&D was sponsored by the US Air Force Reseach Lab (AFRL). During a Phase I STTR contract in 2007, Pikewerks founder Sandy Ring implemented Linux kernel integrity checks and cross-view analysis in a framework she called "Scouts". Under a subsequent Phase II STTR contract that ran from 2008 to 2009, Andrew Tappert and Tom O'Connor developed the software for Linux kernel integrity verification via memory forensics, codenamed "pH", that would become Second Look.

Second Look publicly debuted at the DoD Cyber Crime Conference in St. Louis in January 2009. The first supported distributions were CentOS and Ubuntu (32-bit only). Subsequent internally-funded R&D at Pikewerks led to the first hosted reference kernel repository, supporting automated Linux memory forensics, and 64-bit support. Product releases and backend infrastructure work in 2010 expanded the set of supported kernel versions and distros to include CentOS, Fedora, Red Hat Enterprise Linux (RHEL), and Ubuntu.

In 2011, commercial sales of the product picked up, and it was used to investigate some high profile compromises involving Linux server infrastructure. In December 2011, Pikewerks was acquired by Raytheon, joining its IIS business unit. The year 2012 saw development of the pagehash-based process integrity verification technique, expanding the scope of memory forensics-based verification beyond the kernel. In 2012 the Enterprise edition of Second Look was launched, which performed automated Linux memory forensics scans at scale (the original mode of operation was ad hoc acquisition and analysis during investigations). Debian was added as a supported distribution. In 2014, Second Look gained structured data output (JSON format) and more supported distributions (Amazon Linux and Oracle Linux). Also in 2014, the product and its development team joined Raytheon's Cyber Products group. In 2015, Raytheon Cyber Products was spun out into a joint venture with Websense, and the product was marketed as SureView Memory Integrity. The product got a web interface in 2015, replacing the legacy Qt-based GUI, and new capabilities for automatically extracting artifacts from memory. In 2016, the Raytheon-Websense joint venture was named Forcepoint, and the product was called Threat Protection for Linux. The scope of memory integrity verification was further expanded in 2016 with the addition of cached file verification features, and an advanced alert filtering framework was added. As of 2017, the product is known as Forcepoint Linux Security, and is deployed around the world to enhance the security of large-scale Linux-based IT infrastructure.


Second Look provides memory acquisition capabilities (local and remote), which preserve the volatile system state, capturing evidence and information that does not exist on disk and may otherwise be lost as an investigation proceeds. A command-line script allows for local acquisition of memory from running systems without introducing any additional software. A memory access driver is provided for use on systems without a native interface to physical memory. Remote memory acquisition is facilitated by a memory access agent installed on target systems.

Second Look analyzes live system memory (local or remote), or captured memory images or virtual machine snapshots. It can help to detect, investigate, and reverse engineer malware, including stealthy rootkits and backdoors. A kernel integrity verification approach is utilized to compare the Linux kernel in memory with a reference kernel. Forcepoint provides thousands of reference kernels derived from original distribution kernel packages, and a script for creating reference kernels for other systems, such as those running custom kernels. Forcepoint also maintains a database of pagewise hashes (pagehashes) of the executable files from millions of Linux software packages, to facilitate the identification of those files in memory (in active processes or page cache content). Users can add pagehashes for custom and third-party software to a local reference data repository to facilitate their verification. This enables Second Look to detect unknown and unauthorized applications as well as stealthy user-level malware.

Supported Systems

Second Look is regularly updated to support analysis of the latest kernels and the most commonly used Linux distributions. As of March 2017:

  • Supported target kernels: 2.6.9 through 4.8
  • Supported target architectures: x86 32- and 64-bit
  • Supported target distributions: Amazon Linux, CentOS, Debian, Fedora, Oracle Linux, SUSE, RHEL, and Ubuntu