Biblio

Since 2018, a broad class of microarchitectural attacks called transient execution attacks (e.g., Spectre and Meltdown) have been disclosed. By abusing speculative execution mechanisms in modern CPUs, these attacks enable adversaries to leak secrets across security boundaries. A transient execution attack typically evolves through multiple stages, termed the attack chain. We find that current transient execution attacks usually rely on static attack chains, resulting in that any blockage in an attack chain may cause the failure of the entire attack. In this paper, we propose a novel defense-aware framework, called TEADS, for synthesizing transient execution attacks dynamically. The main idea of TEADS is that: each attacking stage in a transient execution attack chain can be implemented in several ways, and the implementations used in different attacking stages can be combined together under certain constraints. By constructing an attacking graph representing combination relationships between the implementations and testing available paths in the attacking graph dynamically, we can finally synthesize transient execution attacks which can bypass the imposed defense techniques. Our contributions include: (1) proposing an automated defense-aware framework for synthesizing transient execution attacks, even though possible combinations of defense strategies are enabled; (2) presenting an attacking graph extension algorithm to detect potential attack chains dynamically; (3) implementing TEADS and testing it on several modern CPUs with different protection settings. Experimental results show that TEADS can bypass the defenses equipped, improving the adaptability and durability of transient execution attacks.

The keys generated by (symmetric or asymmetric) have been still compromised by attackers. Cryptography algorithms need extra efforts to enhance the security of keys that are transferring between parities. Also, using cryptography algorithms increase time consumption and overhead cost through communication. Encryption is very important issue for protecting information from stealing. Unfortunately encryption can achieve confidentiality not integrity. Covert channel allows two parties to indirectly send information, where the main drawbacks of covert channel are detectability and the security of pre-agreement knowledge. In this paper, i merge between encryption, authentication and convert channel to achieve un-detectability covert channel. This channel guarantee integrity and confidentiality of covert data and sending data dynamically. I propose and implement un-detectability a covert channel using AES (Advanced Encryption Standard) algorithm and HMAC (Hashed Message Authentication Code). Where this channel is un-detectability with integrity and confidentiality agreement process between the sender and the receiver. Instead of sending fake key directly through channel, encryption and HMAC function used to hide fake key. After that investigations techniques for improving un-detectability of channel is proposed.