What action is typically indicative of a passive attack in a WLAN environment?

In a WLAN environment, a passive attack is characterized by the act of monitoring network traffic without making any alterations to it. This type of attack focuses on collecting information rather than disrupting or changing the data flow. An attacker engaged in passive activities may utilize tools to observe network communications, looking for sensitive data such as passwords, personal information, or unencrypted transmissions.

This method does not raise immediate alarms because the integrity of the network is maintained, and users are often unaware that their data is being intercepted. The information gathered can later be exploited for more serious attacks, such as active attacks or unauthorized access.

The other options depict active forms of attack, which involve direct interference with the network or its users. Unauthorized access to user credentials implies a breach where an attacker gains control over accounts. Broadcasting false information involves sending misleading data into the network to misinform users or compromise systems. Injecting malicious software entails modifying the environment to introduce harmful code, both of which are aggressive actions and therefore not considered passive attacks.