CVE-2023-41991Apple Multiple Products Improper Certificate Validation Vulnerability
CVE-2023-41991 is a improper certificate validation in Apple iOS and iPadOS, rated medium (5.5 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
TLS certificates are not checked properly, so an attacker on the path can pose as the server.
How it is reached
An attacker can exploit it by someone who can already run code or sign in on the machine, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
A successful attack can change data or behaviour. In practice, this kind of flaw lets an attacker read or tamper with traffic, or pass a forged message as genuine.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2023-09-25: it is being exploited in the wild. EPSS estimates a 13% chance of exploitation activity in the next 30 days, higher than 96% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2023-10-16.
- Upgrade Apple iOS and iPadOS to 16.7 or later. Other affected products have their own fixed versions on this page.
- Limit who can run code or sign in on the hosts that run it.
- Warn the people who use it, and filter files and links on the way in.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
A certificate validation issue was addressed. This issue is fixed in macOS Ventura 13.6, iOS 16.7 and iPadOS 16.7. A malicious app may be able to bypass signature validation. Apple is aware of a report that this issue may have been actively exploited against versions of iOS before iOS 16.7.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Operating systems on servers, workstations or devices. Everything on the host inherits the flaw.
- TLS termination and service-to-service channels. The flaw sits on the network path between clients and services.
- Signature checks. The flaw sits on the network path between clients and services.
Trust boundaries in play
- Host boundary. The attacker needs a foothold on the machine first; the flaw turns a small foothold into a bigger one.
- People who open files and links. Mail, chat and browsers are the delivery path.
- On the network path between clients and services. An attacker who crosses it can read or tamper with traffic, or pass a forged message as genuine.
Questions to answer about your own systems
- Where does Apple iOS and iPadOS run in your systems, and at which version?
- Which of those hosts also run code or users you do not fully trust?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.