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THREATINT
PUBLISHED

CVE-2023-46139

KernelSU signature validation mismatch



AssignerGitHub_M
Reserved2023-10-16
Published2023-10-30
Updated2024-09-05

Description

KernelSU is a Kernel based root solution for Android. Starting in version 0.6.1 and prior to version 0.7.0, if a KernelSU installed device is infected with a malware whose app signing block specially constructed, it can take over root privileges on the device. The vulnerable verification logic actually obtains the signature of the last block with an id of `0x7109871a`, while the verification logic during Android installation is to obtain the first one. In addition to the actual signature upgrade that has been fixed (KSU thought it was V2 but was actually V3), there is also the problem of actual signature downgrading (KSU thought it was V2 but was actually V1). Find a condition in the signature verification logic that will cause the signature not to be found error, and KernelSU does not implement the same conditions, so KSU thinks there is a V2 signature, but the APK signature verification actually uses the V1 signature. This issue is fixed in version 0.7.0. As workarounds, keep the KernelSU manager installed and avoid installing unknown apps.



MEDIUM: 5.0CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:L

Problem types

CWE-863: Incorrect Authorization

Product status

>= 0.6.1, < 0.7.0
affected

References

https://github.com/tiann/KernelSU/security/advisories/GHSA-86cp-3prf-pwqq

https://github.com/tiann/KernelSU/commit/d24813b2c3738f2f9bd762932141cadd948c354f

https://drive.google.com/drive/folders/1XdYCCAhC_mkt1k1IyUiwcgFsuOFvwNRl

https://github.com/tiann/KernelSU/blob/344c08bb79ba12b692016750cda363f9f3500182/kernel/apk_sign.c#L179C32-L179C32

https://github.com/tiann/KernelSU/blob/344c08bb79ba12b692016750cda363f9f3500182/kernel/apk_sign.c#L188

http://aospxref.com/android-14.0.0_r2/xref/frameworks/base/core/java/android/util/apk/ApkSigningBlockUtils.java#770

http://aospxref.com/android-14.0.0_r2/xref/frameworks/base/core/java/android/util/apk/ApkSigningBlockUtils.java#783

cve.org CVE-2023-46139

nvd.nist.gov CVE-2023-46139

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