CVE-2022-43699 in OX App Suite
Summary
by MITRE • 04/15/2023
OX App Suite before 7.10.6-rev30 allows SSRF because e-mail account discovery disregards the deny-list and thus can be attacked by an adversary who controls the DNS records of an external domain (found in the host part of an e-mail address).
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Analysis
by VulDB Data Team • 05/03/2023
The vulnerability CVE-2022-43699 affects OX App Suite versions prior to 7.10.6-rev30 and represents a critical server-side request forgery flaw that stems from improper email account discovery mechanisms. This vulnerability specifically exploits the application's failure to properly enforce deny-list restrictions during the email address validation process, creating a pathway for attackers to manipulate the system's behavior through DNS record manipulation. The flaw exists in the host portion of email addresses where the application performs account discovery without adequate validation of external domain references.
The technical implementation of this vulnerability involves the application's email account discovery routine which attempts to verify email addresses by making network requests to the domain portion of email addresses. When an attacker controls the DNS records of an external domain used in an email address, they can manipulate the resolution process to redirect requests to internal systems or sensitive endpoints that should normally be inaccessible. This creates a scenario where the application's internal security controls are bypassed because the deny-list mechanisms are effectively ignored during the discovery phase, allowing unauthorized access to internal resources that would otherwise be protected.
From an operational impact perspective, this vulnerability enables adversaries to perform reconnaissance and potentially gain access to internal systems that are not directly exposed to the internet. The attack vector leverages DNS manipulation rather than traditional network-level attacks, making it particularly challenging to detect and prevent. An attacker can construct malicious email addresses pointing to domains they control, then observe the application's behavior when it attempts to validate these addresses, potentially revealing internal network topology, accessing internal services, or even performing further exploitation. This type of vulnerability directly impacts the principle of least privilege and can lead to information disclosure, lateral movement, and potentially complete system compromise.
The vulnerability aligns with CWE-918, Server-Side Request Forgery, which specifically addresses flaws where applications make untrusted requests to internal resources. It also maps to ATT&CK technique T1071.004, Application Layer Protocol: DNS, where adversaries use DNS to bypass network restrictions and access internal systems. The attack surface is particularly concerning because email account discovery is a common function that typically requires minimal user interaction, making this vulnerability exploitable through various attack vectors including phishing campaigns, social engineering, or automated scanning. Organizations should implement immediate mitigations including updating to OX App Suite 7.10.6-rev30 or later, implementing proper network segmentation, and establishing robust DNS monitoring to detect unauthorized modifications to critical domains. Additionally, network-level controls such as firewalls and proxy configurations should be enhanced to prevent outbound requests to internal addresses from external-facing applications, while also implementing DNS security measures to prevent unauthorized DNS record changes that could enable similar attacks.