CVE-2018-25338: Zechat 1.5 SQL Injection Vulnerability

CVE-2018-25338 Overview

CVE-2018-25338 is a SQL injection vulnerability [CWE-89] in Zechat 1.5 that affects the hashtag parameter. Unauthenticated attackers can submit union-based payloads through the parameter to extract arbitrary data from the backend database. The flaw allows remote attackers to enumerate table names, column names, and stored records without any authentication or user interaction. Public exploitation details were published in Exploit-DB entry 44685, and a corresponding advisory was issued by VulnCheck.

Critical Impact

Unauthenticated remote attackers can extract database contents from Zechat 1.5 deployments using union-based SQL injection against the hashtag parameter.

Affected Products

• Zechat 1.5
• Deployments hosting the vulnerable hashtag endpoint
• Web applications bundling the affected Zechat component

Discovery Timeline

• 2026-05-17 - CVE-2018-25338 published to NVD
• 2026-05-18 - Last updated in NVD database

Technical Details for CVE-2018-25338

Vulnerability Analysis

The vulnerability resides in how Zechat 1.5 processes the hashtag request parameter. The application concatenates the user-supplied value directly into a SQL query without parameterization or input sanitization. Attackers can append UNION SELECT statements to the parameter, causing the database engine to merge attacker-controlled result sets with the legitimate query response.

Because the endpoint is reachable without authentication, exploitation requires no valid session, cookie, or token. Public exploit code in Exploit-DB entry 44685 demonstrates retrieval of table and column metadata from information_schema, which attackers use to map the schema before extracting records. The defect is classified under CWE-89 (Improper Neutralization of Special Elements used in an SQL Command).

Root Cause

The root cause is the absence of prepared statements or input validation around the hashtag parameter. User input flows directly into the SQL string, allowing query structure manipulation through standard SQL metacharacters.

Attack Vector

The attack vector is network-based over HTTP. An attacker crafts a request with a malicious hashtag value containing union-based payloads and observes the application's response to extract data row by row. No privileges or user interaction are required. Refer to the Exploit-DB entry 44685 and the VulnCheck Advisory on Zechat SQL Injection for payload structure and reproduction steps.

Detection Methods for CVE-2018-25338

Indicators of Compromise

• HTTP requests containing UNION, SELECT, information_schema, or encoded SQL keywords within the hashtag parameter.
• Repeated requests to the hashtag endpoint from a single source enumerating sequential offsets or column counts.
• Web server logs showing unusually long hashtag parameter values or non-printable characters.
• Database error messages or stack traces returned in HTTP responses tied to hashtag queries.

Detection Strategies

• Deploy web application firewall rules that flag SQL keywords and union-based patterns in the hashtag parameter.
• Inspect application access logs for query strings matching known payloads documented in Exploit-DB entry 44685.
• Enable database query auditing to surface queries referencing information_schema.tables or information_schema.columns originating from the application user.

Monitoring Recommendations

• Alert on HTTP 500 responses from the hashtag endpoint, which often indicate failed injection attempts.
• Monitor outbound data volumes from the database tier for anomalous read patterns consistent with bulk extraction.
• Correlate request bursts against the hashtag endpoint with downstream database CPU spikes.

How to Mitigate CVE-2018-25338

Immediate Actions Required

• Restrict public access to the vulnerable hashtag endpoint through network ACLs or authentication gates until a fix is in place.
• Apply web application firewall signatures that block SQL metacharacters in the hashtag parameter.
• Audit database accounts used by Zechat and enforce least privilege so the application user cannot read information_schema or unrelated tables.

Patch Information

No vendor patch is referenced in the available advisories. Operators of Zechat 1.5 should consult the Bylancer Security Resource and the VulnCheck Advisory on Zechat SQL Injection for upgrade guidance or replacement components.

Workarounds

• Implement server-side input validation that rejects any non-alphanumeric characters in the hashtag parameter.
• Replace dynamic SQL concatenation with parameterized queries or prepared statements in the affected handler.
• Place the application behind a reverse proxy that normalizes and inspects query parameters before they reach Zechat.
• Rotate database credentials and review historical access logs for prior exploitation activity.