30Z_firmware: Incorrect Default Permissions
CVE-2023-38295 is a high-severity incorrect default permissions vulnerability in 30Z_firmware from Tcl, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected 30Z_firmware versions: SP1A.210812.016. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.18% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of 30Z_firmware you run against the affected versions below, and install the vendor's latest release.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Tcl | 30Z_firmware | SP1A.210812.016 | Not stated |
| Tcl | 10L_firmware | RKQ1.210107.001 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Certain software builds for the TCL 30Z and TCL 10 Android devices contain a vulnerable, pre-installed app that relies on a missing permission that provides no protection at runtime. The missing permission is required as an access permission by components in various pre-installed apps. On the TCL 30Z device, the vulnerable app has a package name of com.tcl.screenrecorder (versionCode='1221092802', versionName='v5.2120.02.12008.1.T' ; versionCode='1221092805', versionName='v5.2120.02.12008.2.T'). On the TCL 10L device, the vulnerable app has a package name of com.tcl.sos (versionCode='2020102827', versionName='v3.2014.12.1012.B'). When a third-party app declares and requests the missing permission, it can interact with certain service components in the aforementioned apps (that execute with "system" privileges) to perform arbitrary files reads/writes in its context. An app exploiting this vulnerability only needs to declare and request the single missing permission and no user interaction is required beyond installing and running a third-party app. The software build fingerprints for each confirmed vulnerable device are as follows: TCL 10L (TCL/T770B/T1_LITE:11/RKQ1.210107.001/8BIC:user/release-keys) and TCL 30Z (TCL/4188R/Jetta_ATT:12/SP1A.210812.016/LV8E:user/release-keys, TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU5P:user/release-keys, TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU61:user/release-keys, TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU66:user/release-keys, TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU68:user/release-keys, TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU6P:user/release-keys, and TCL/T602DL/Jetta_TF:12/SP1A.210812.016/vU6X:user/release-keys). This malicious app declares the missing permission named com.tct.smart.switchphone.permission.SWITCH_DATA as a normal permission, requests the missing permission, and uses it to interact with the com.tct.smart.switchdata.DataService service component that is declared in vulnerable apps that execute with "system" privileges to perform arbitrary file reads/writes.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.
How developers prevent this class of flaw
- The architecture needs to access and modification attributes for files to only those users who actually require those actions.
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
More Incorrect Default Permissions vulnerabilities (CWE-276)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in 30Z_firmware
- 8.8 High severity
- 8.0 High severity
Recent Incorrect Default Permissions vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 8.8 High severity
- 7.8 High severity
- 9.1 Critical severity
- 7.8 High severity
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