CVE-2019-8901 in iOS
Summary
by MITRE • 10/28/2020
This issue was addressed by verifying host keys when connecting to a previously-known SSH server. This issue is fixed in iOS 13.1 and iPadOS 13.1. An attacker in a privileged network position may be able to intercept SSH traffic from the “Run script over SSH” action.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 11/29/2020
The vulnerability described in CVE-2019-8901 represents a significant security flaw in iOS and iPadOS systems that affects SSH (Secure Shell) connections. This issue specifically impacts the authentication process when establishing secure connections to previously known SSH servers through the "Run script over SSH" functionality. The vulnerability arises from insufficient host key verification mechanisms that allow for potential man-in-the-middle attacks in privileged network positions.
The technical flaw stems from the absence of proper host key verification when connecting to SSH servers that have been previously encountered by the system. This creates an opportunity for attackers positioned within the network to intercept and potentially manipulate SSH traffic without detection. The vulnerability manifests when users execute the "Run script over SSH" action, which is commonly used for remote system administration and automated tasks. Without proper host key validation, the system fails to confirm that the SSH server being connected to is indeed the legitimate server intended by the user, opening the door for attackers to present fake server identities.
The operational impact of this vulnerability is substantial for organizations relying on iOS devices for secure remote administration tasks. Attackers with privileged network access can intercept SSH communications and potentially inject malicious commands or steal sensitive information transmitted through these connections. This threat is particularly concerning because SSH is widely used for critical system administration tasks, automated deployments, and secure remote access to sensitive infrastructure. The vulnerability essentially undermines the fundamental security assurances that SSH provides, making it possible for attackers to compromise the integrity and confidentiality of remote execution workflows.
The fix implemented in iOS 13.1 and iPadOS 13.1 addresses this issue by enforcing proper host key verification mechanisms during SSH connections. This remediation aligns with established security practices outlined in the CWE (Common Weakness Enumeration) framework, specifically addressing CWE-310, which deals with cryptographic issues related to key management and verification. The solution follows ATT&CK framework techniques for privilege escalation and credential access by ensuring that the authentication process properly validates server identities before establishing secure connections. Organizations should prioritize updating to these versions to mitigate the risk of interception attacks and maintain the integrity of their remote administration processes. The vulnerability highlights the importance of maintaining robust host key verification practices in secure communication protocols and demonstrates how seemingly minor authentication gaps can create significant security risks in enterprise environments.