Apple has released macOS Big Sur 11.6, iOS/iPadOS 14.8 and Safari 14.1.2 to fix two security flaws (CVEs), tracked as CVE-2021-30858 and CVE-2021-30860. According to the company, both of the vulnerabilities are zero-days that may have been exploited in the wild.
The first zero-day, CVE-2021-30858, is a Use After Free vulnerability that stems from improper memory handling in the WebKit. Due to the vulnerability, an attacker can conduct arbitrary code execution attacks on vulnerable products.
The second zero-day, CVE-2021-30860, is an Integer Overflow vulnerability that exist in the Apple’s image rendering library (CoreGraphics). Due to the vulnerability, an attacker can run arbitrary code on the vulnerable products via a maliciously crafted PDF.
Dubbed as FORCEDENTRY, CVE-2021-30860 has been reported by the Citizen Lab. The company announced that the FORCEDENTRY vulnerability was discovered while analyzing a phone infected with NSO Group’s Pegasus spyware. Citizen Lab also noted that they believed FORCEDENTRY has been exploited since at least February 2021.
Note that FORCEDENTRY does not exist in Safari web browser. However, iPhones/iPads (iOS/iPadOS versions prior to 14.8), Mac computers (prior to macOS Big Sur 11.6) and Apple watches (prior to watchOS 7.6.2) are affected from the vulnerability.
An attacker who successfully exploits the CVE-2021-30858 by causing memory corruption (Use After Free) in WebKit via a crafted HTML page, could remotely execute arbitrary code and gain full control of the system.
Impact Summary CVE-2021-30858
Category: Use After Free
CVSS 3.1 Base Score: N/A
CVSS 3.1 Vector: N/A
An attacker who successfully exploits the CVE-2021-30860 by causing Integer overflow in the memory via a maliciously crafted PDF, could execute arbitrary code and gain full control of the system.
Impact Summary CVE-2021-30860
Category: Integer Overflow
CVSS 3.1 Base Score: 7.8 High
CVSS 3.1 Vector: AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
To defend against possible attacks due to these zero-day vulnerabilities (CVE-2021-30858, CVE-2021-30860), Apple released macOS Big Sur 11.6, iOS/iPadOS 14.8 and Safari 14.1.2. Affected products needs to be updated to the latest versions immediately.
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References to Advisories, Solutions and Tools
- https://nvd.nist.gov (CVE-2021-30858)
- https://nvd.nist.gov (CVE-2021-30860)
- Apple Security Updates – macOS
- Apple Security Updates – iOS and iPadOS
- Apple Security Updates – Safari
- The Citizen Lab Report – FORCEDENTRY