Information disclosure in Ti Tm4c123
CVE-2018-18056
An issue was discovered in the Texas Instruments (TI) TM4C, MSP432E and MSP432P microcontroller series. The eXecute-Only-Memory (XOM) implementation prevents code read-outs on protected memory by generating bus faults. However, single-stepping and using breakpoints is allowed in XOM-protected flash memory. As a consequence, it is possible to execute single instructions with arbitrary system states (e.g., registers, status flags, and SRAM content) and observe the state changes produced by the unknown instruction. An attacker could exploit this vulnerability by executing protected and unknown instructions with specific system states and observing the state changes. Based on the gathered information, it is possible to reverse-engineer the executed instructions. The processor acts as a kind of "instruction oracle."
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.6 (Medium). Vector: CVSS:3.0/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.004 (32.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 32.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
References
- www.usenix.org/system/files/woot19-paper_schink.pdf (Technical Description, Third Party Advisory)
- www.usenix.org/conference/woot19/presentation/schink (Technical Description, Third Party Advisory)
Frequently asked questions
- What is CVE-2018-18056?
- CVE-2018-18056 is a medium-severity vulnerability in Ti Tm4c123, classified under Information Disclosure. CVSS score: 4.6/10. Published 2019-08-20.
- How severe is CVE-2018-18056?
- Medium severity. CVSS v3 base score is 4.6 out of 10.