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Symmetric denial of service - FTP


The server crash is generated with multiple requests with the functionality Configuration and Programming Reverse Homologation that takes time to process the information when making the request with the selected SFTP (SSH) protocol, causing a 504 error in the application.


Cause a denial of service.


Define a time-out when a query or a search is taking too long to process the information.


Authenticated attacker in the application.

Expected Remediation Time

⌚ 60 minutes.


Default score using CVSS 3.1. It may change depending on the context of the vulnerability.


  • Attack vector: N
  • Attack complexity: L
  • Privileges required: L
  • User interaction: N
  • Scope: U
  • Confidentiality: N
  • Integrity: N
  • Availability: H


  • Exploit code madurity: X
  • Remediation level: X
  • Report confidence: X


  • Vector string: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:X/RL:X/RC:X
  • Score:
    • Base: 6.5
    • Temporal: 6.5
  • Severity:
    • Base: Medium
    • Temporal: Medium

Code Examples

Compliant code

Potentially large queries include a timeout limit to avoid overloading

void initStatement(Connection conn, Statement stmt) throws SQLException {
int queryTimeout = 3600;
try {
rs = stmt.executeQuery(validateQuery);
return true;
} catch {
//Throw exception when query takes two long

Non compliant code

The application performs potentially large queries without setting a timeout limit

void initStatement(Connection conn, Statement stmt) throws SQLException {
int queryTimeout = 3600;
rs = stmt.executeQuery(validateQuery);
//Handle query without limiting its time to execute


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