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Two-Factor Authentication Interception

Use of two- or multifactor authentication is recommended and provides a higher level of security than user names and passwords alone, but organizations should be aware of techniques that could be used to intercept and bypass these security mechanisms. Adversaries may target authentication mechanisms, such as smart cards, to gain access to systems, services, and network resources.

If a smart card is used for two-factor authentication (2FA), then a keylogger will need to be used to obtain the password associated with a smart card during normal use. With both an inserted card and access to the smart card password, an adversary can connect to a network resource using the infected system to proxy the authentication with the inserted hardware token. [1]

Adversaries may also employ a keylogger to similarly target other hardware tokens, such as RSA SecurID. Capturing token input (including a user's personal identification code) may provide temporary access (i.e. replay the one-time passcode until the next value rollover) as well as possibly enabling adversaries to reliably predict future authentication values (given access to both the algorithm and any seed values used to generate appended temporary codes). [2]

Other methods of 2FA may be intercepted and used by an adversary to authenticate. It is common for one-time codes to be sent via out-of-band communications (email, SMS). If the device and/or service is not secured, then it may be vulnerable to interception. Although primarily focused on by cyber criminals, these authentication mechanisms have been targeted by advanced actors. [3]

ID: T1111

Tactic: Credential Access

Platform:  Linux, Windows, macOS

Permissions Required:  Administrator, SYSTEM

Data Sources:  API monitoring, Process monitoring, Kernel drivers

Contributors:  John Lambert, Microsoft Threat Intelligence Center

Version: 1.0

Examples

NameDescription
Sykipot

Sykipot is known to contain functionality that enables targeting of smart card technologies to proxy authentication for connections to restricted network resources using detected hardware tokens.[4]

Mitigation

Remove smart cards when not in use. Protect devices and services used to transmit and receive out-of-band codes.

Identify and block potentially malicious software that may be used to intercept 2FA credentials on a system by using whitelisting [5] tools, like AppLocker, [6] [7] or Software Restriction Policies [8] where appropriate. [9]

Detection

Detecting use of proxied smart card connections by an adversary may be difficult because it requires the token to be inserted into a system; thus it is more likely to be in use by a legitimate user and blend in with other network behavior.

Similar to Input Capture, keylogging activity can take various forms but can may be detected via installation of a driver, setting a hook, or usage of particular API calls associated with polling to intercept keystrokes.

References