RT-Labs AB C-Open CANopen contains a write protection bypass in the SDO (Service Data Object) server implementation 'src/co_sdo_server.c' that fails to properly validate write permissions when processing download-segment frames. An unauthenticated attacker on the CAN bus can initiate an SDO upload for a read-only Object Dictionary (OD) entry, which sets a data pointer to the read-only object, then send download-segment frames to write to that memory location. The download-segment handler does not verify that a download session is active, allowing any CANopen node to overwrite read-only OD entries using two SDO frames. Note that CANopen protocol operates over CAN bus and does not provide built-in authentication mechanisms. Fixed in 1.1.1.
CVSS Details
- CVSS 4.0 Base Score: 7.1 (HIGH)
- CVSS 4.0 Vector: (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
- CVSS 3.1 Base Score: 6.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N)
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