There is a new open source framework designed for automatically generating antivirus signatures from malware.
The tool, named BASS, is an automated signature synthesizer, said researchers at Cisco’s Talos intelligence and research group.
The framework creates signatures from malware belonging to previously generated clusters and its main goals are to improve resource usage and make malware analysis easier, Talos researchers said in a blog post.
The idea behind BASS is to reduce the resource usage of Cisco’s ClamAV open source antivirus engine by generating more pattern-based signatures instead of hash-based signatures, officials said. On top of that, the tool can also cut down on the workload of analysts who write pattern-based signatures.
The Python-based framework employs a cluster of Docker containers, which allows for scalability, and it leverages web services to interact with other tools.
Thousands of signatures are added to the ClamAV database every day and most are hash-based. The problem with hash-based signatures, compared to bytecode- and pattern-based signatures, is a signature is used to identify a single file instead of an entire malware cluster. This has several disadvantages, including a bigger memory footprint.
Pattern-based signatures are easier to maintain compared to bytecode signatures, which is why Cisco prefers this type of signature.
The BASS framework takes malware clusters from various sources and each file is unpacked using ClamAV unpackers. Once the malware cluster is filtered to ensure the files correspond to the input expected by BASS (i.e. Portable Executable files), the binaries are disassembled using IDA Pro or other disassembler, and the tool searches the samples for common code that can be used to generate the signature.
The source code for the Alpha version of BASS is available on GitHub.