The IMF Conference is the International Conference on IT Security Incident
Management & IT Forensics. This year it took place from May 23 to 24 in Munich.
The schedule lists
a lot of interesting talks.
One of the talks was my presentation on a paper about Ceph forensics, based on
my Master Thesis:
The concept of Software Defined Storage (SDS) has become very popular over the
last few years. It is used in public, private, and hybrid clouds to store
enterprise, private, and other kinds of data. Ceph is an
open-source software that implements an SDS stack.
At this years ARES conference, Jonas Plum (Siemens) and me (Andreas Dewald, ERNW Research GmbH) published a paper about the forensic analysis of APFS, file system internals and presented different methodologies for file recovery. We also publicly released a tool implementing our presented approaches, called afro (APFS file recovery).
APFS is the file system for Apple devices that is used by default on all current iOS mobile devices, as well as macOS since High Sierra, and is thus currently rolled out on a large number of devices. By using afro, we evaluated and compared the different approaches amongst each other and identified the method that so far delivers the best results and compared it to photorec. This showed that AFRO outperforms photorec on the evaluated APFS dataset. In the presentations of this research we were often asked if other tools like Blackbags Blacklight do not already support this recovery process. So, we decided to compare the file recovery capabilities of BlackLight and afro. We wanted to compare afro to the sleuth kit as well, as at the DFRWS conference it was discussed about adding APFS Support to The Sleuthkit Framework, but no implementations are public yet.
the last post was about a fuse filesystem which provides a read-only access to the proprietary bluecoat filesystem. After some further investigations based on the possibilities this offered us, I started to implement a tool which allows to modify parts of the filesystem.
Protection Mechanisms
Since last time, the discovered filesystem structures still had unknown fields. Some of those fields could be reconstructed and their purpose in the whole construct. The format of the Partition-Header for example could now be described as
You may remember our last post regarding the SGOS system and the proprietary file system. Since then, we got access to a newer version of the system (6.6.4.2). Still not the most current one (which seems to be 6.7.1.1) nor of the 6.6.x branch (which seems to be 6.6.5.1) though. As this system version also used the same proprietary filesystem (although it initially booted from a FAT32 partition), I decided to take a deeper look into this.