CVE-2017-7088 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11 is affected. The issue involves the "Exchange ActiveSync" component. It allows remote attackers to erase a device in opportunistic circumstances by hijacking a cleartext AutoDiscover V1 session during the setup of an Exchange account.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-7088 represents a critical security flaw within Apple's iOS operating system affecting versions prior to iOS 11. This weakness resides within the Exchange ActiveSync component, which serves as the primary protocol for mobile email synchronization between iOS devices and corporate email servers. The vulnerability stems from insufficient security measures during the initial account setup process, specifically when the system utilizes cleartext AutoDiscover V1 sessions to determine Exchange server configuration details. This design flaw creates a window of opportunity for remote attackers to exploit the communication channel between the mobile device and the email server.
The technical implementation of this vulnerability exploits the lack of encryption during the AutoDiscover process, which operates in cleartext mode by default. When users configure Exchange email accounts on their iOS devices, the system sends a cleartext request to the email server to automatically discover the correct configuration parameters. Attackers can intercept this communication through man-in-the-middle attacks, particularly in unsecured network environments such as public wifi networks or compromised corporate networks. The attacker's ability to hijack this session allows them to manipulate the AutoDiscover response, potentially redirecting the device to a malicious server or injecting false configuration data that enables unauthorized device erasure capabilities.
The operational impact of this vulnerability extends beyond simple data loss, as it provides attackers with the capability to remotely wipe entire devices without user consent or knowledge. This represents a significant escalation from typical email security threats to full device compromise scenarios, particularly affecting enterprise users who rely on iOS devices for business communication. The opportunistic nature of the attack means that adversaries can exploit this vulnerability even when users are not actively using their devices, making detection extremely difficult. Organizations with mobile device management policies may be particularly vulnerable since the attack can occur during the initial setup phase before security policies are properly enforced, creating a critical window of exposure that can be exploited by threat actors.
This vulnerability aligns with CWE-319, which addresses the exposure of sensitive information through cleartext transmission, and demonstrates characteristics consistent with ATT&CK technique T1566.001, involving the use of spearphishing attachments or links to gain initial access. The attack vector specifically targets the device setup phase, making it particularly dangerous as it occurs before normal security controls are typically implemented. Organizations should implement network segmentation to prevent cleartext traffic interception, deploy encrypted AutoDiscover services, and ensure all iOS devices are updated to versions that properly encrypt AutoDiscover sessions. Additionally, security awareness training should emphasize the importance of avoiding untrusted networks during initial device configuration, as the vulnerability can be exploited even when users are not actively engaged in email management activities. The remediation approach requires both immediate patching of affected iOS versions and long-term network security improvements to prevent similar vulnerabilities in related protocols and services.