Cryptographic Side-Channel Vulnerability

A cryptographic side-channel vulnerability is a weakness in a cryptographic system that can be exploited through information gained from the physical implementation of the system, rather than through weaknesses in the algorithms or protocols themselves. Examples of side-channel information include timing information, power consumption, and electromagnetic radiation emitted by the system. Attackers can use this information to infer secret keys and other sensitive information, potentially compromising the security of the system.

It occurs when an attacker can extract secret information from a cryptographic system by analyzing information that is leaked through a side-channel, such as timing, power consumption, electromagnetic radiation, or the sound of a device. This type of attack is possible because many cryptographic algorithms have specific patterns in their computations that can reveal information about the secret key. For example, a timing attack can be performed by measuring the time it takes for a cryptographic operation to complete. If an attacker can correlate the timing of the operation with the secret key, they can extract the key. A power analysis attack can be performed by measuring the power consumption of a device during a cryptographic operation. If an attacker can correlate the power consumption with the secret key, they can extract the key.

Mitigating side-channel attacks requires careful design of the cryptographic algorithm and implementation. This includes using techniques like constant-time algorithm, masking, and fault injection countermeasures.

It occurs when an attacker can extract secret information from a cryptographic system by analyzing information that is leaked through a side-channel, such as timing, power consumption, electromagnetic radiation, or the sound of a device;
Timing: A cryptographic operation may take longer to execute depending on the value of the secret key, and an attacker can measure this time to extract the key.

Power consumption: A cryptographic operation may consume more or less power depending on the value of the secret key, and an attacker can measure this power consumption to extract the key.

Electromagnetic radiation: A cryptographic operation may produce electromagnetic radiation that can reveal information about the secret key.

Sound: A cryptographic operation may produce sounds that can reveal information about the secret key.

Cache-based side-channel: Modern processors use cache memory to speed up the execution of instructions, cryptographic operations may cause cache-based side-channel leaks and an attacker can use this to extract the key.

Side-channel attack can also occur in the use of a specific hardware like smart-cards, TPMs, and other embedded systems. These side-channel attacks take advantage of the physical properties of the cryptographic implementation and not the mathematical properties of the algorithm itself.

There are several tools available to detect cryptographic side-channel vulnerabilities. Some of these include:
Side-Channel Analysis Toolkit (SCA-TK): This is a collection of open-source tools for analyzing
power consumption, electromagnetic radiation, and other side-channel information.

DPA Contest: This is an open-source framework for analyzing power consumption and timing side-channel information. It includes a set of tools for data acquisition, data analysis, and attack development.

Side-Channel Leakage Estimation (SLE): This is a tool for estimating the amount of leakage present in a cryptographic implementation based on power consumption or electromagnetic radiation measurements.

AES-NI Side-Channel Analyzer (ASCA): This is a tool for analyzing power consumption and electromagnetic radiation side-channels in AES implementations that use the AES-NI instruction set.

SCA-Shield: This is a tool for automatically protecting cryptographic implementations against side-channel attacks.

T-Walk: This is a tool for discovering and analyzing side-channel vulnerabilities in embedded systems.

SPA-Tools: This is a set of tools for analyzing power consumption side-channels in smart cards and other embedded systems.

It is important to note that these tools are not exhaustive and new tools are constantly being developed. Also, it is important to consider that these tools are not a silver bullet and it's important to combine them with other methodologies and techniques to have a comprehensive assessment.

In 2011, researchers discovered a vulnerability in the way the Intel's Sandy Bridge and Ivy Bridge microprocessors handled AES encryption. The vulnerability allowed an attacker to extract the encryption key by analyzing the power consumption of the CPU during the encryption process. This vulnerability, known as the AES-NI vulnerability, affected many systems and devices that used the affected microprocessors. 

Also in 2018, the microprocessors of modern computers and mobile devices were affected with this vulnerability named Meltdown and Spectre that allows an attacker to access sensitive data by exploiting the way a microprocessor handles speculative execution. This vulnerability affects processors from multiple vendors, including Intel, AMD, and ARM, and can be used to extract sensitive information such as encryption keys, passwords, and other secret data.

The risks associated with cryptographic side-channel vulnerabilities include:
Confidentiality breach: An attacker can extract sensitive information such as encryption keys, passwords, and other secret data by analyzing information leaked through a side-channel.

Authentication bypass: An attacker can use information leaked through a side-channel to bypass authentication mechanisms and gain unauthorized access to a system or network.

Data tampering: An attacker can use information leaked through a side-channel to tamper with data, such as injecting false information into a system.

Reputation damage: A cryptographic side-channel vulnerability can lead to a data breach and compromise sensitive information, which can cause significant damage to an organization's reputation.

Legal liability: A data breach caused by a cryptographic side-channel vulnerability can lead to legal action and financial penalties.

Compliance failure: A cryptographic side-channel vulnerability can lead to non-compliance with industry or government regulations, which can result in fines and penalties.

Lack of trust: A cryptographic side-channel vulnerability can cause a lack of trust in the security of the system, making it difficult to attract and retain customers.

It is important to note that side-channel attacks can be especially dangerous when used in conjunction with other types of attacks such as malware, phishing and social engineering.