CVE-2017-18382 in cPanel
Summary
by MITRE
cPanel before 68.0.15 allows use of an unreserved e-mail address in DNS zone SOA records (SEC-306).
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Analysis
by VulDB Data Team • 07/18/2020
The vulnerability CVE-2017-18382 affects cPanel versions prior to 68.0.15 and relates to improper validation of email addresses within DNS zone SOA (Start of Authority) records. This issue stems from the software's failure to properly validate email addresses when they are used in DNS zone configuration files, specifically in the SOA record format where email addresses are typically encoded using the standard DNS zone file syntax. The problem occurs when cPanel accepts email addresses that do not conform to standard DNS zone file requirements for email address encoding, particularly in the context of unreserved email addresses that may contain special characters or formatting that could be exploited.
The technical flaw manifests in how cPanel processes and stores email addresses within DNS zone files, where email addresses are expected to follow the DNS standard format of replacing the @ symbol with a single dot in the zone file representation. However, the vulnerable versions of cPanel do not properly validate that email addresses conform to these requirements, allowing potentially malformed or malicious email addresses to be stored in DNS zone files. This vulnerability is particularly concerning because DNS zone files are critical infrastructure components that control domain name resolution and can be manipulated by attackers to cause various forms of disruption or exploitation.
The operational impact of this vulnerability extends beyond simple configuration issues and can potentially enable several attack vectors. An attacker with access to cPanel configuration capabilities could manipulate DNS zone files to include malformed email addresses that might be processed differently by various DNS resolvers or tools, potentially leading to DNS cache poisoning, denial of service conditions, or even information disclosure through crafted email address formats. The vulnerability affects the integrity of DNS zone data and could be exploited to create confusion in DNS resolution processes or to bypass certain security controls that rely on proper email address validation in DNS records.
This vulnerability aligns with CWE-20, which describes "Improper Input Validation" and falls under the broader category of configuration management flaws that can lead to security issues in web hosting environments. The issue also relates to ATT&CK technique T1059.001, which covers command and scripting interpreter usage, as attackers might leverage the DNS configuration flaws to manipulate system behavior through crafted zone records. Organizations using cPanel systems should prioritize updating to version 68.0.15 or later, as this release includes proper validation of email addresses in DNS zone files. Additionally, administrators should implement monitoring for unusual DNS zone file modifications and ensure that proper access controls are in place to limit who can modify DNS configurations within cPanel environments. Regular security audits of DNS zone files and proper input sanitization practices should be implemented to prevent similar issues from arising in other systems that handle DNS configuration data.