CAPE: Malware Configuration And Payload Extraction
CAPE is a malware sandbox. It is derived from Cuckoo and is designed to automate the process of malware analysis with the goal of extracting payloads and configuration from malware.
This allows CAPE to detect malware based on payload signatures, as well as automating many of the goals of malware reverse engineering and threat intelligence.
CAPE can detect a number of malware techniques or behaviours, as well as specific malware families, from its initial run on a sample.
This detection may then trigger a further run with a specific package, in order to extract the malware payload and possibly its configuration, for further analysis.
CAPE works by controlling malware via a bespoke debugger and API hooks. Detection to trigger a CAPE package can be based on API or Yara signatures. The debugger uses Yara signatures or API hooks to allow breakpoints to be set on individual instructions, memory regions or function calls. Once a region of interest is reached, it can be manipulated and dumped for processing and analysis, and possibly configuration parsing.
The techniques or behaviours that CAPE detects and has packages for include:
- Process injection
- Shellcode injection
- DLL injection
- Process Hollowing
- Decompression of executable modules in memory
- Extraction of executable modules or shellcode in memory
Packages for these behaviours will dump the payloads being injected, extracted or decompressed for further analysis. This is often the malware payload in unpacked form.
CAPE automatically creates a process dump for each process, or, in the case of a DLL, the DLL’s module image in memory. This is useful for samples packed with simple packers, where often the module image dump is fully unpacked. Yara signatures may trigger on the process dumps, possibly resulting in submission with a specific package or configuration parsing.
CAPE also has a package which can dynamically unpack samples that use ‘hacked’ (modified) UPX, very popular with malware authors. These samples are run in CAPE’s debugger until their OEP (original entry point), whereupon they are dumped, fixed and their imports are automatically reconstructed, ready for analysis.
Currently, CAPE has specific packages dumping configuration and payloads for the following malware families:
- PlugX
- EvilGrab
- Sedreco
- Cerber
- Ursnif
CAPE has config parsers/decoders for the following malware families, whose payloads are extracted by a behavioural package:
- RedLeaf
- ChChes
- HttpBrowser
- Enfal
- PoisonIvy
- TrickBot
- RCSession/Screech
The CAPE debugger allows four breakpoints to be set on read, write or execute of a memory address or region, as well as single-step mode. This allows fine control over malware execution until it is possible to dump the memory regions of interest, containing code or configuration data. Breakpoints can be set dynamically by package code, API hooks or Yara signatures. Thanks to the embedded distorm library the debugger can output the disassembly of instructions during single-step mode or when breakpoints are hit.
Processes, modules and memory regions can variously be dumped by CAPE through use of a simple API. These dumps can then be scanned and parsed for configuration information.
