Query: mitigate Downgrade Attack
Matching passage: T1689 Downgrade Attack. Tactics: defense impairment. Description: Adversaries may downgrade or use a version of system features that may be outdated, vulnerable, and/or does not support updated security controls.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](https://attack.mitre.org/techniques/T1059) or even network protocols that can be abused to enable [Adversary-in-the-Middle](https://attack.mitre.org/techniques/T1557) or [Network Sniffing](https://attack.mitre.org/techniques/T1040).(Citation: Praetorian TLS Downgrade Attack 2014) For example, [PowerShell](https://attack.mitre.org/techniques/T1059/001) 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)
Near-miss passage: T1553.006 Code Signing Policy Modification. Tactics: defense impairment. Description: Adversaries may modify code signing policies to enable execution of unsigned or self-signed code. Code signing provides a level of authenticity on a program from a developer and a guarantee that the program has not been tampered with. Security controls can include enforcement mechanisms to ensure that only valid, signed code can be run on an operating system. Some of these security controls may be enabled by default, such as Driver Signature Enforcement (DSE) on Windows or System Integrity Protection (SIP) on macOS.(Citation: Microsoft DSE June 2017)(Citation: Apple Disable SIP) Other such controls may be disabled by default but are configurable through application controls, such as only allowing signed Dynamic-Link Libraries (DLLs) to execute on a system. Since it can be useful for developers to modify default signature enforcement policies during the development and testing of applications, disabling of these features may be possible with elevated permissions.(Citation: Microsoft Unsigned Driver Apr 2017)(Citation: Apple Disable SIP) Adversaries may modify code signing policies in a number of ways, including through use of command-line or GUI utilities, [Modify Registry](https://attack.mitre.org/techniques/T1112), rebooting the computer in a debug/recovery mode, or by altering the value of variables in kernel memory.(Citation: Microsoft TESTSIGNING Feb 2021)(Citation: Apple Disable SIP)(Citation: FireEye HIKIT Rootkit Part 2)(Citation: GitHub Turla Driver Loader) Examples of commands that can modify the code signing policy of a system include <code>bcdedit.exe -set TESTSIGNING ON</code> on Windows and <code>csrutil disable</code> on macOS.(Citation: Microsoft TESTSIGNING Feb 2021)(Citation: Apple Disable SIP) Depending on the implementation, successful modification of a signing policy may require reboot of the compromised system. Additionally, some implementations can introduce visible artifacts for the user (ex: a watermark in the corner of the screen stating the