T1689 Downgrade Attack

Adversaries may downgrade or use a version of system features that may be outdated, vulnerable, and/or does not support updated security controls. Downgrade attacks typically take advantage of a system’s backward compatibility to force it into less secure modes of operation.

Adversaries may downgrade and use various less-secure versions of features of a system, such as Command and Scripting Interpreter or even network protocols that can be abused to enable Adversary-in-the-Middle or Network Sniffing.(Citation: Praetorian TLS Downgrade Attack 2014) For example, PowerShell versions 5+ includes Script Block Logging (SBL), which can record executed script content. However, adversaries may attempt to execute a previous version of PowerShell that does not support SBL with the intent to impair defenses while running malicious scripts that may have otherwise been detected.(Citation: CrowdStrike downgrade attack)(Citation: Google Cloud downgrade attack)(Citation: att_def_ps_logging)

Adversaries may similarly target network traffic to downgrade from an encrypted HTTPS connection to an unsecured HTTP connection that exposes network data in clear text.(Citation: Targeted SSL Stripping Attacks Are Real)(Citation: CrowdStrike Downgrade attack 2) On Windows systems, adversaries may downgrade the boot manager to a vulnerable version that bypasses Secure Boot, granting the ability to disable various operating system security mechanisms.(Citation: SafeBreach)