[BugTales] Exploiting CSN.1 Bugs in MediaTek Basebands
This summer at Black Hat, we have published research about exploiting Huawei basebands (video recording also available here). The remote code execution attack surface explored in that work was the Radio Resource stack’s CSN.1 decoder. Searching for bugs in CSN.1 decoding turned out to be very fruitful in the case of Huawei’s baseband, however, they were not the only vendor that we looked at - or that had such issues. Around at the same time that we investigated Huawei’s baseband, we also looked into the same attack surface in the baseband of MediaTek Helio chipsets. As the timelines in our advisories (1, 2, 3, 4) show, these vulnerabilities were reported way back in December 2019 and the MediaTek security advisories were released in September 2021 initially and updated in January 2022.