We have identified a new stack buffer overflow vulnerability in Mediatek’s Linux Kernel driver implementation of cellular-to-application processor communication interface (CCCI). The vulnerability can be exploited by a malicious (compromised) baseband runtime to achieve arbitrary code execution in the Linux Kernel. The vulnerability we are disclosing in this advisory affected a wide range of Mediatek devices, including phones on the newest chipsets (Dimensity 700, 1000, etc). The July 2022 issue of the Mediatek Security Bulletin contains this vulnerability as CVE-2022-21766. Vulnerability Details There is a kernel stack buffer overflow vulnerability in the implementation of the modem-kernel communication interface. The stack overflow can be used to overwrite the return address of a kernel function, with attacker controlled data.

We have identified a new heap buffer overflow vulnerability in Mediatek’s baseband implementation. The vulnerability can be exploited to achieve arbitrary code execution in the baseband runtime. The vulnerability we are disclosing in this advisory affected a wide range of Mediatek devices, including phones on the newest chipsets (Dimensity 700, 1000, etc). The July 2022 issue of the Mediatek Security Bulletin contains this vulnerability as CVE-2022-21744. Vulnerability Details The GPRS Packet Neighbour Cell Data (PNCD) message is an optional message sent by the network on the PACCH to provide system information required for initial access in a neighbouring cell. In the case of the MediaTek baseband firmware, this message is processed in the FDD_rmpc_mac_rmpc_pncd_ind_hdlr function.

We have identified a new out-of-bound write vulnerability in Mediatek’s Linux Kernel driver implementation of cellular-to-application processor communication interface (CCCI). The vulnerability can be exploited by a malicious (compromised) baseband runtime to achieve arbitrary code execution in the Linux Kernel. The vulnerability we are disclosing in this advisory affected a wide range of Mediatek devices, including phones on the newest chipsets (Dimensity 700, 1000, etc). The July 2022 issue of the Mediatek Security Bulletin contains this vulnerability as CVE-2022-21765. Vulnerability Details There is a vmalloc out-of-bound write vulnerability in the kernel implementation of the modem-kernel communication interface. The out-of-bound write can be used to write controlled data, with controlled size, at a controlled location within the kernel’s vmalloc memory region.

We have identified a new out-of-bound read vulnerability in Mediatek’s Linux Kernel driver implementation of cellular-to-application processor communication interface (CCCI). The vulnerability can be exploited by a malicious (compromised) baseband runtime to leak information from the kernel runtime and break the kernel’s entropy-based mitigations such as KASLR and stack smashing protection. The vulnerability we are disclosing in this advisory affected a wide range of Mediatek devices, including phones on the newest chipsets (Dimensity 700, 1000, etc). The July 2022 issue of the Mediatek Security Bulletin contains this vulnerability as CVE-2022-21769. Vulnerability Details There is a vmalloc out-of-bound read vulnerability in the kernel implementation of the modem-kernel communication interface.

Summary In this advisory we are disclosing a heap overflow vulnerability in the MediaTek baseband. The vulnerability can be exploited to gain arbitrary code execution in the context of the baseband runtime. The vulnerability was fixed in 2020 in some models, and received a CVE and more widely deployed fix in 2021. Vulnerability Details When processing the CSN.1 decoding of the “E-UTRAN Individual Priority Parameters” element, the function rr_decode_eutran_individual_priority_para_description implements a two-depth nested repetition (Repeated Individual E-UTRAN Priority Parameters Description struct and its child element EARFCN). The outer loop is iterated by checking on the single bit representing the ongoing repetition, and while that equals “1”, a new Repeated Individual E-UTRAN Priority Parameters Description struct is processed.

Summary In this advisory we are disclosing a heap overflow vulnerability in the MediaTek baseband. The vulnerability can be exploited to gain arbitrary code execution in the context of the baseband runtime. The vulnerability was fixed in 2020 in some models, and received a CVE and more widely deployed fix in 2021. Vulnerability Details When processing the CSN.1 decoding of the “UTRAN (3G) Individual Priority Parameters” element, the function rr_decode_3g_individual_priority_para_description implements a two-depth nested repetition (Repeated Individual UTRAN Priority Parameters Description struct and its child element FDD-ARFCN). The outer loop is iterated by checking the single bit representing the ongoing repetition, and while that equals “1”, a new Repeated Individual UTRAN Priority Parameters Description struct is processed.

Summary In this advisory we are disclosing a heap overflow vulnerability in the MediaTek baseband. The vulnerability can be exploited to gain arbitrary code execution in the context of the baseband runtime. The vulnerability was fixed in 2020 in some models, and received a CVE and more widely deployed fix in 2021. Vulnerability Details When processing the CSN.1 decoding of the “E-UTRAN IPP with extended EARFCNs” element, the function rr_decode_eutran_ipp_extended_earfcns implements a two-depth nested repetition (Repeated Individual E-UTRAN PP with extended EARFCNs Description struct and its child element EARFCN_extended). The outer loop is iterated by checking the single bit representing the ongoing repetition, and while that equals “1”, a new Repeated Individual E-UTRAN PP with extended EARFCNs Description struct is processed.

Summary In this advisory we are disclosing a heap overflow vulnerability in the MediaTek baseband. The vulnerability can be exploited to gain arbitrary code execution in the context of the baseband runtime. The vulnerability was fixed in 2020 in some models, and received a CVE and more widely deployed fix in 2021. Vulnerability Details When processing the GSM Radio Resource Management Channel Release message, the CSN.1 decoding of the “Cell selection indicator after release of all TCH and SDCCH” information element contains a heap buffer overflow in the function FDD_csrr_decode_redirection_ie. The “Cell selection indicator after release of all TCH and SDCCH” is a type 4 information element with a minimum length of 4 octets.