Abstract
Nowadays, most cyber attackers exploit secure communication channels to hide malicious activities and imitate the behaviors of a legitimate user. These attacks over a secure channel make networked systems more vulnerable to new threats and increase the possibility of significant damage to other end users. Traditional TCP/IP-level traffic inspections do not suffice in investigating a secure sockets layer (SSL) conversation because the SSL conversation data is encrypted by a public key system and the SSL uses its own data unit of an SSL record. In this paper, we propose a novel malicious SSL traffic detection method, which reassembles SSL records from captured IP packets and inspects the characteristics of SSL records using a deep learning method. After an SSL record is reassembled from a single or multiple IP packets, the proposed method extracts unencrypted contents of the reassembled record and generates a sequence of unencrypted data from successive SSL records for deep learning-based classification. The sequences of SSL records are encoded using a long short-term memory autoencoder, and then an encoded feature map is generated for each SSL flow. These feature maps are forwarded to the convolutional neural network-based classifier to determine whether the SSL flow is malicious or not. The experiment shows that our proposed approach has a great separability between benign and malicious traffic flows on an encrypted SSL channel.
Funding Information
  • National Research Foundation (NRF) through the Ministry of Science and ICT (MSIT) of Korean Government (2020R1F1A1060941)
  • Institute of Information and Communications Technology Planning and Evaluation (IITP) funded by the Korea Government (2017-0-00421)
  • IITP funded by MSIT through the Artificial Intelligence Graduate School Program (2019-0-01842)

This publication has 30 references indexed in Scilit: