CVE-2021-38375 in OX App Suite
Summary
by MITRE • 11/22/2021
OX App Suite through 7.10.5 allows XSS via the alt attribute of an IMG element in a truncated e-mail message.
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Analysis
by VulDB Data Team • 11/25/2021
The vulnerability identified as CVE-2021-38375 represents a cross-site scripting flaw within the OX App Suite email client platform version 7.10.5 and earlier. This security weakness specifically manifests when processing email messages containing image elements with maliciously crafted alt attributes, creating a persistent threat vector that can be exploited by attackers to execute arbitrary JavaScript code in the context of a victim's browser session. The vulnerability stems from insufficient input validation and sanitization mechanisms within the email rendering engine that fails to properly escape or filter user-supplied content before displaying it in the web interface.
The technical exploitation of this vulnerability occurs through the manipulation of the alt attribute within HTML img tags embedded in email messages. When an attacker crafts a malicious email containing an image element with a specially crafted alt attribute, the vulnerable application fails to adequately sanitize this input during the email preview or display process. This allows the malicious JavaScript code contained within the alt attribute to execute when the email is rendered in a user's browser, particularly affecting the truncated email message view where the full content may be obscured but the malicious payload remains active. The flaw operates at the application layer and specifically targets the web-based email client interface, making it particularly dangerous in enterprise environments where email is a primary communication channel.
The operational impact of this vulnerability extends beyond simple script execution to potentially enable full session hijacking, data exfiltration, and privilege escalation within the email platform. An attacker could leverage this vulnerability to steal user credentials, access sensitive email communications, or establish persistent backdoors within the organization's email infrastructure. The vulnerability affects all users of the affected OX App Suite versions who are exposed to malicious email content, creating a significant risk for organizations that do not maintain strict email filtering policies or user education programs. The attack vector is particularly concerning because it can be delivered through standard email channels without requiring any special privileges or complex attack chains, making it accessible to threat actors of varying skill levels.
Organizations should implement immediate mitigations including applying the vendor-provided security patches for OX App Suite version 7.10.5 and later, implementing strict email content filtering policies, and enhancing user awareness training regarding suspicious email content. The vulnerability aligns with CWE-79, which describes cross-site scripting flaws in web applications, and maps to ATT&CK technique T1566.001 for the initial access phase through spearphishing attachments. Additional protective measures should include implementing content security policies, disabling inline scripting in email rendering contexts, and establishing network-level email filtering to prevent malicious content from reaching end users. Security teams should also monitor for indicators of compromise related to this vulnerability and consider implementing email sandboxing solutions to analyze suspicious content before delivery.