Forensic analysis of memory on Linux
Tracing Clues
In computer forensics, memory analysis is becoming increasingly important as a means for investigating security incidents. In this article, we provide an overview of the various memory dumping options on Linux and introduce the support in Linux for the Volatility Analysis Framework.
Experts agree that one of the first steps for diagnosing a potential intrusion incident is backing up a RAM image. Traditional investigations of persistent memory are no longer sufficient because, as the capacity of hard drives increases, you need to investigate a huge amount of data to detect an attack. Analysis of volatile memory can support and accelerate these investigations because forensic investigators only need to search through a comparatively small amount of data for clues relating to a successful attack. Additionally, RAM often contains important traces, such as information on running processes or active network connections.
Tapping into RAM is especially important for countering anti-forensics techniques. In some cases, it is possible to extract the passphrase for an encrypted drive from volatile memory. You can also detect non-persistent malware using RAM analysis. In targeted attacks, hackers often use malicious code that is only active in memory, and it leaves no data behind on the disk [1] [2]. This type of malware is virtually undetectable without analyzing volatile memory.
Much of the industry focus has been on developing memory analysis techniques for Windows operating systems. Recently, though, security specialists have identified a growing number of attacks on Linux-based systems, such as data center servers, embedded devices, and Android phones. The potential threats have led to a resurgence of interest in Linux RAM analysis. In this article, I describe some popular tools for RAM analysis in Linux and provide an example showing how to look for intruders with the versatile Volatility forensic analysis application.
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