Apple iOS Kernel Memory Information Disclosure & KASLR Bypass (CVE-2016-4655, Pegasus/Trident)
Executive & SecOps Summary
SECOPS ASSESSMENTAll Apple iOS devices running versions prior to iOS 9.3.5
Local attackers or malicious apps can read sensitive kernel memory, allowing them to bypass Kernel Address Space Layout Randomization (KASLR) and facilitate full system compromise
Immediately update all affected iOS devices to iOS 9.3.5 or later
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
The primary remediation is to upgrade the operating system to iOS 9.3.5 or later. For enterprise environments, enforce the update via Mobile Device Management (MDM) systems.
2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, restrict the installation of enterprise-signed apps and block access to unknown configuration profiles using MDM policies.
# Conceptual MDM payload restriction to disable untrusted enterprise apps
# <key>allowEnterpriseAppTrust</key>
# <false/>3. Log Audit & IoC Verification Commands
Use the following Swift code snippet within your mobile security auditing tools to identify vulnerable iOS devices in your network inventory:
import UIKit
let currentOS = UIDevice.current.systemVersion
let safeOS = '9.3.5'
if currentOS.compare(safeOS, options: .numeric) == .orderedAscending {
print('[ALERT] Vulnerable iOS version detected: \(currentOS)')
} else {
print('[INFO] Device is secure. iOS version: \(currentOS)')
}Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
CVE-2016-4655 is a critical information disclosure vulnerability in the Apple iOS kernel. The root cause lies in the kernel's improper validation and handling of memory structures, which allows a crafted application to read sensitive data directly from kernel memory space.
2. Exploitation Mechanics & Attack Scenario
This vulnerability was actively exploited in the wild as part of the 'Trident' exploit chain used by the Pegasus spyware. In a typical attack scenario, a victim is lured into visiting a malicious website, triggering a WebKit vulnerability (CVE-2016-4657) to escape the browser sandbox. Once inside, the attacker leverages CVE-2016-4655 to read kernel memory and determine the base address of the kernel, effectively bypassing KASLR. With KASLR defeated, the attacker can reliably execute a kernel memory corruption exploit (CVE-2016-4656) to gain root privileges and install persistent spyware.
3. Infrastructure & Business Impact
As a CISA KEV-listed vulnerability with a high EPSS score, this flaw poses a severe threat to enterprise mobile security. Successful exploitation allows threat actors to silently compromise iOS devices, leading to the theft of sensitive corporate communications, credentials, location data, and real-time audio/video surveillance without the user's knowledge.
Official Vendor Advisories & References
The kernel in Apple iOS before 9.3.5 allows attackers to obtain sensitive information from memory via a crafted app.
Frequently Asked SecOps Questions (CVE-2016-4655)
FAQQ1. How critical is CVE-2016-4655 and is it actively exploited in the wild?
CVE-2016-4655 is rated CVSS 5.5 (MEDIUM) with a 30-day EPSS exploitation probability of 33.4%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2016-4655?
Primary impacted vendors include apple across ios. Scope summary: All Apple iOS devices (iPhone, iPad, iPod touch) running iOS versions prior to 9.3.5
Q3. What temporary mitigations or workarounds exist for CVE-2016-4655 before patching?
[Mitigation] Immediately update all affected iOS devices to iOS 9.3.5 or later Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2016-4655
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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