The Internet of Things (IoT) is a major trend that is seen as a great opportunity to improve efficiency in many domains, including agriculture. This technology could transform the sector, improving the management and quality of agricultural operations, for example, crop farming. The most promising data transmission standard for this domain seems to be Long Range Wide Area Network (LoRaWAN), a popular representative of low power wide area network technologies today. LoRaWAN, like any wireless protocol, has properties that can be exploited by attackers, which has been a topic of multiple research papers in recent years. By conducting a systematic literature review, we build a recent list of attacks, as well as collect mitigation options. Taking a look at a concrete use case (IoT in agriculture) allows us to evaluate the practicality of both exploiting the vulnerabilities and implementing the countermeasures. We detected 16 attacks that we grouped into six attack types. Along with the attacks, we collect countermeasures for attack mitigation. Developers can use our findings to minimize the risks when developing applications based on LoRaWAN. These mostly theoretical security recommendations should encourage future works to evaluate the mitigations in practice.