Problem
Research questions and friction points this paper is trying to address.
ASN.1
UPER
parser verification
security vulnerabilities
protocol compliance
VUPER: Verified ASN.1 UPER Parser
🤖 AI Summary
This work addresses the lack of formal verification in ASN.1 UPER parsers widely deployed in safety-critical systems, which poses correctness and security risks. We present the first bit-precise formal semantics for ASN.1 UPER and introduce VUPER, a comprehensive framework integrating formal modeling, verified combinators, a compiler, and a test oracle based on a formally verified parser. Our approach supports both forward and backward compatibility and has uncovered 20 distinct classes of inconsistencies across seven open-source and four commercial parsers, revealing concrete attack vectors. The results demonstrate that VUPER’s strict adherence to the standard significantly outperforms existing implementations in correctness and robustness.
📝 Abstract
ASN.1 is a widely used interface description language, and UPER (Unaligned Packed Encoding Rules) is one of its key encoding rules, particularly popular in security-critical domains such as cellular networks and vehicle-to-everything (V2X) communication. To ensure the correctness and security of this foundational infrastructure, we present VUPER, a framework for generating verified ASN.1 UPER parsers. We first formalize the notion of a bit-precise parser and identify properties that prove round-trip consistency for parsers and serializers, while accounting for ASN.1 features such as backward/forward compatibility. We then implement and verify parser and serializer combinators for ASN.1 basic types and structures, while adhering to the UPER specification. We also develop a compiler that translates ASN.1 definitions into verified parsers. Finally, we develop a dynamic testing framework using the VUPER parser as a test oracle. To empirically evaluate our approach, we test 7 open-source and 4 commercial ASN.1 parsers using 5G and V2X communication protocols. VUPER uncovers 20 types of inconsistencies in popular parsers and demonstrates stricter compliance with ASN.1 UPER standards. Additionally, we demonstrate concrete attacks by exploiting these parser vulnerabilities.
Innovation
Methods, ideas, or system contributions that make the work stand out.
verified parser
ASN.1 UPER
formal verification
round-trip consistency
protocol security
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