AutoProfile: Towards Automated Profile Generation for Memory Analysis

Despite a considerable number of approaches that have been proposed to protect computer systems, cyber-criminal activities are on the rise and forensic analysis of compromised machines and seized devices is becoming essential in computer security. This article focuses on memory forensics, a branch of digital forensics that extract artifacts from the volatile memory. In particular, this article looks at a key ingredient required by memory forensics frameworks: a precise model of the OS kernel under analysis, also known as profile . By using the information stored in the profile, memory forensics tools are able to bridge the semantic gap and interpret raw bytes to extract evidences from a memory dump. A big problem with profile-based solutions is that custom profiles must be created for each and every system under analysis. This is especially problematic for Linux systems, because profiles are not generic : they are strictly tied to a specific kernel version and to the configuration used to build the kernel. Failing to create a valid profile means that an analyst cannot unleash the true power of memory forensics and is limited to primitive carving strategies. For this reason, in this article we present a novel approach that combines source code and binary analysis techniques to automatically generate a profile from a memory dump, without relying on any non-public information. Our experiments show that this is a viable solution and that profiles reconstructed by our framework can be used to run many plugins, which are essential for a successful forensics investigation.

Memory Layout Extraction and Verification Method for Reliable Physical Memory Acquisition

Physical memory acquisition is a prerequisite when performing memory forensics, referring to a set of techniques for acquiring and analyzing traces associated with user activity information, malware analysis, cyber incident response, and similar areas when the traces remain in the physical RAM. However, certain types of malware have applied anti-memory forensics techniques to evade memory analysis strategies or to make the acquisition process impossible. To disturb the acquisition process of physical memory, an attacker hooks the kernel API, which returns a map of the physical memory spaces, and modifies the return value of the API, specifically that typically used by memory acquisition tools. Moreover, an attacker modifies the kernel object referenced by the kernel API. This causes the system to crash during the memory acquisition process or causes the memory acquisition tools to incorrectly proceed with the acquisition. Even with a modification of one byte, called a one-byte modification attack, some tools fail to acquire memory. Therefore, specialized countermeasure techniques are needed for these anti-memory forensics techniques. In this paper, we propose a memory layout acquisition method which is robust to kernel API hooking and the one-byte modification attack on NumberOfRuns, the kernel object used to construct the memory layout in Windows. The proposed acquisition method directly accesses the memory, extracts the byte array, and parses it in the form of a memory layout. When we access the memory, we extract the _PHYSICAL_MEMORY_DESCRIPTOR structure, which is the basis of the memory layout without using the existing memory layout acquisition API. Furthermore, we propose a verification method that selects a reliable memory layout. We realize the verification method by comparing NumberOfRuns and the memory layout acquired via the kernel API, the registry, and the proposed method. The proposed verification method guarantees the reliability of the memory layout and helps secure memory image acquisition through a comparative verification with existing memory layout acquisition methods. We also conduct experiments to prove that the proposed method is resistant to anti-memory forensics techniques, confirming that there are no significant differences in time compared to the existing tools.

Real-Time Triggering of Android Memory Dumps for Stealthy Attack Investigation

Attackers regularly target Android phones and come up with new ways to bypass detection mechanisms to achieve long-term stealth on a victim’s phone. One way attackers do this is by leveraging critical benign app functionality to carry out specific attacks.In this paper, we present a novel generalised framework, JIT-MF (Just-in-time Memory Forensics), which aims to address the problem of timely collection of short-lived evidence in volatile memory to solve the stealthiest of Android attacks. The main components of this framework are i) Identification of critical data objects in memory linked with critical benign application steps that may be misused by an attacker; and ii) Careful selection of trigger points, which identify when memory dumps should be taken during benign app execution.The effectiveness and cost of trigger point selection, a cornerstone of this framework, are evaluated in a preliminary qualitative study using Telegram and Pushbullet as the victim apps targeted by stealthy malware. Our study identifies that JIT-MF is successful in dumping critical data objects on time, providing evidence that eludes all other forensic sources. Experimentation offers insight into identifying categories of trigger points that can strike a balance between the effort required for selection and the resulting effectiveness and storage costs. Several optimisation measures for the JIT-MF tools are presented, considering the typical resource constraints of Android devices.