Overview
CVE-2021-47941 describes a SQL injection vulnerability in the WordPress Plugin Survey & Poll 1.5.7.3 that allowed unauthenticated attackers to inject arbitrary SQL via the wp_sap cookie parameter, enabling data exfiltration of usernames, passwords, and other confidential data from the WordPress database. This vulnerability is categorized under CWE-89 (SQL Injection). While the CVE references a PHP-based WordPress component, the underlying risk-unsafely incorporating untrusted input into SQL queries-is generalizable to any web application, including Go (Gin) services. The impact of such injections in the wild is severe, often permitting unauthorized data access, escalation, or modification. This guide references CVE-2021-47941 to illustrate the real-world danger of cookie- or header-driven SQL injection patterns and maps that risk into Go (Gin) development practices. It emphasizes the importance of parameterized queries and input validation to prevent similar exploit paths in Go services.
Code Fix Example
Go (Gin) API Security Remediation
package main
import (
"database/sql"
"log"
"net/http"
"github.com/gin-gonic/gin"
_ "github.com/go-sql-driver/mysql"
)
var db *sql.DB
func initDB() {
var err error
// Replace with real DSN and least-privilege credentials
db, err = sql.Open("mysql", "user:pass@tcp(127.0.0.1:3306)/mydb")
if err != nil {
log.Fatal(err)
}
}
// Vulnerable pattern: unsafe string concatenation using untrusted input from a cookie
func vulnerableHandler(c *gin.Context) {
sap, _ := c.Cookie("sap")
// DO NOT DO THIS: vulnerable to SQL injection if sap is attacker-controlled
query := "SELECT id, username, email FROM users WHERE username = '" + sap + "'"
rows, err := db.Query(query)
if err != nil {
c.String(http.StatusInternalServerError, "query error")
return
}
defer rows.Close()
c.String(http.StatusOK, "vulnerable result")
}
// Fixed pattern: parameterized queries to prevent injection
func fixedHandler(c *gin.Context) {
sap, _ := c.Cookie("sap")
rows, err := db.Query("SELECT id, username, email FROM users WHERE username = ?", sap)
if err != nil {
c.String(http.StatusInternalServerError, "query error")
return
}
defer rows.Close()
c.String(http.StatusOK, "safe result")
}
func main() {
initDB()
r := gin.Default()
r.GET("/vulnerable", vulnerableHandler)
r.GET("/fixed", fixedHandler)
r.Run(":8080")
}