T1521.002_asymmetric-cryptography

T1521.002 Asymmetric Cryptography

Sub-technique of: T1521

High-Level Description

Adversaries may employ a known asymmetric encryption algorithm to conceal command and control traffic, rather than relying on any inherent protections provided by a communication protocol. Asymmetric cryptography, also known as public key cryptography, uses a keypair per party: one public that can be freely distributed, and one private that should not be distributed. Due to how asymmetric algorithms work, the sender encrypts data with the receiver’s public key and the receiver decrypts the data with their private key. This ensures that only the intended recipient can read the encrypted data. Common public key encryption algorithms include RSA, ElGamal, and ECDSA.

For efficiency, many protocols (including SSL/TLS) use symmetric cryptography once a connection is established, but use asymmetric cryptography to establish or transmit a key. As such, these protocols are classified as Asymmetric Cryptography.

Kill Chain Phase

• Command and Control (TA0037)

Platforms: Android, iOS

What to Check

• Identify if Asymmetric Cryptography technique is applicable to target mobile environment
• Check Android devices for indicators of Asymmetric Cryptography
• Check iOS devices for indicators of Asymmetric Cryptography
• Assess detection coverage (1 detection strategies)

How to Test

Identify Attack Surface

Determine if the target mobile environment is susceptible to Asymmetric Cryptography by examining the target platforms (Android, iOS).

Assess Existing Defenses

Review whether mitigations for T1521.002 are in place. If defenses are absent or misconfigured, this technique may be exploitable.

Remediation Guide

No specific mitigations documented for this technique.

Detection

Detection of Asymmetric Cryptography

Risk Assessment

CWE Categories

References

• MITRE ATT&CK Mobile - T1521.002