1. A computer-implemented method for detecting illegitimate out-of-band authentication attempts, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: determining that a text message comprises a confirmation code for an out-of-band authentication procedure based on at least one of: a format of the text message; a source of text message; detecting an attempt to access the text message; determining that the attempt to access the text message was configured to avoid participation by a user of a device on which the attempt to access the text message occurred; performing, in response to determining both that the attempt to access the text message was configured to avoid participation by the user and that the text message comprises the confirmation code for the out-of-band authentication procedure, a remediation action that addresses an illegitimate out-of-band authentication attempt, the illegitimate out-of-band authentication attempt comprising the attempt to access the text message, wherein performing the remediation action comprises at least one of: blocking the attempt to access the text message; warning a user of the attempt; warning a sender of the text message of the attempt; disabling an application with a permission to access text messages.
1. A computer-implemented method for detecting illegitimate out-of-band authentication attempts, at least a portion of the method being performed by a computing device comprising at least one processor, the method comprising: determining that a text message comprises a confirmation code for an out-of-band authentication procedure based on at least one of: a format of the text message; a source of text message; detecting an attempt to access the text message; determining that the attempt to access the text message was configured to avoid participation by a user of a device on which the attempt to access the text message occurred; performing, in response to determining both that the attempt to access the text message was configured to avoid participation by the user and that the text message comprises the confirmation code for the out-of-band authentication procedure, a remediation action that addresses an illegitimate out-of-band authentication attempt, the illegitimate out-of-band authentication attempt comprising the attempt to access the text message, wherein performing the remediation action comprises at least one of: blocking the attempt to access the text message; warning a user of the attempt; warning a sender of the text message of the attempt; disabling an application with a permission to access text messages. 3. The computer-implemented method of claim 1 , wherein: the attempt to access the text message comprises an attempt to forward the text message; determining that the attempt to access the text message was configured to avoid participation by the user comprises determining that the attempt to forward the text message happened within a suspiciously short amount of time according to a predefined suspicion heuristic.