Kingdom: Input Validation and Representation
Input validation and representation problems ares caused by metacharacters, alternate encodings and numeric representations. Security problems result from trusting input. The issues include: "Buffer Overflows," "Cross-Site Scripting" attacks, "SQL Injection," and many others.
Server-Side Template Injection
Abstract
User-controlled data is used as a template engine's template, allowing attackers to access the template context and in some cases inject and run arbitrary code on the application server.
Explanation
Template engines are used to render content using dynamic data. This context data is normally controlled by the user and formatted by the template to generate web pages, emails, and the like. Template engines allow powerful language expressions to be used in templates in order to render dynamic content, by processing the context data with code constructs such as conditionals, loops, etc. If an attacker is able to control the template to be rendered, they will be able to inject expressions that will expose context data or even run arbitrary commands on the server.
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered.
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered.
// Set up the context data
VelocityContext context = new VelocityContext();
context.put( "name", user.name );
// Load the template
String template = getUserTemplateFromRequestBody(request);
RuntimeServices runtimeServices = RuntimeSingleton.getRuntimeServices();
StringReader reader = new StringReader(template);
SimpleNode node = runtimeServices.parse(reader, "myTemplate");
template = new Template();
template.setRuntimeServices(runtimeServices);
template.setData(node);
template.initDocument();
// Render the template with the context data
StringWriter sw = new StringWriter();
template.merge( context, sw );
Example 1 uses Velocity as the template engine. For that engine, an attacker could submit the following template to run arbitrary commands on the server:
$name.getClass().forName("java.lang.Runtime").getRuntime().exec(<COMMAND>)
References
[1] Server-Side Template Injection: RCE for the modern webapp
[2] Standards Mapping - Common Weakness Enumeration CWE ID 95
[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [18] CWE ID 094
[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [17] CWE ID 094
[5] Standards Mapping - Common Weakness Enumeration Top 25 2022 [25] CWE ID 094
[6] Standards Mapping - Common Weakness Enumeration Top 25 2023 [23] CWE ID 094
[7] Standards Mapping - Common Weakness Enumeration Top 25 2024 [11] CWE ID 094
[8] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002754
[9] Standards Mapping - FIPS200 SI
[10] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data
[11] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-10 Information Input Validation (P1)
[12] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-10 Information Input Validation
[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.2.4 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.5 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.8 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)
[14] Standards Mapping - OWASP Mobile 2014 M1 Weak Server Side Controls
[15] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation
[16] Standards Mapping - OWASP Top 10 2004 A6 Injection Flaws
[17] Standards Mapping - OWASP Top 10 2007 A2 Injection Flaws
[18] Standards Mapping - OWASP Top 10 2010 A1 Injection
[19] Standards Mapping - OWASP Top 10 2013 A1 Injection
[20] Standards Mapping - OWASP Top 10 2017 A1 Injection
[21] Standards Mapping - OWASP Top 10 2021 A03 Injection
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.6
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.2
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.1
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.1
[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.1
[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.1
[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.1
[29] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4
[30] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4
[31] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection
[32] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation
[33] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation, Control Objective C.3.2 - Web Software Attack Mitigation
[34] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 116
[35] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3570 CAT I
[36] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3570 CAT I
[37] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3570 CAT I
[38] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3570 CAT I
[39] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3570 CAT I
[40] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3570 CAT I
[41] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3570 CAT I
[42] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002560 CAT I
[43] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002560 CAT I
[44] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002560 CAT I
[45] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002560 CAT I
[46] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002560 CAT I
[47] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002560 CAT I
[48] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002560 CAT I
[49] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002560 CAT I
[50] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002560 CAT I
[51] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002560 CAT I
[52] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002560 CAT I
[53] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002560 CAT I
[54] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002560 CAT I
[55] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[56] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[57] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)
desc.dataflow.java.server_side_template_injection
Abstract
User-controlled data is used as a template engine's template, which allows attackers to access the template context and in some cases inject and run arbitrary code on the application server.
Explanation
Template engines are used to render content using dynamic data. This context data is normally controlled by the user and formatted by the template to generate web pages, emails, and so on. Template engines allow powerful language expressions to be used in templates to render dynamic content, by processing the context data with code constructs such as conditionals, loops, etc. If an attacker can control the template to be rendered, they can inject expressions that expose context data or even run arbitrary commands on the server.
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered.
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered.
app.get('/', function(req, res){
var template = _.template(req.params['template']);
res.write("<html><body><h2>Hello World!</h2>" + template() + "</body></html>");
});
Example 1 uses Underscore.js as the template engine within a Node.js application. For that engine, an attacker could submit the following template to run arbitrary commands on the server:
<% cp = process.mainModule.require('child_process');cp.exec(<COMMAND>); %>
References
[1] Server-Side Template Injection: RCE for the modern webapp
[2] Standards Mapping - Common Weakness Enumeration CWE ID 95
[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [18] CWE ID 094
[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [17] CWE ID 094
[5] Standards Mapping - Common Weakness Enumeration Top 25 2022 [25] CWE ID 094
[6] Standards Mapping - Common Weakness Enumeration Top 25 2023 [23] CWE ID 094
[7] Standards Mapping - Common Weakness Enumeration Top 25 2024 [11] CWE ID 094
[8] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002754
[9] Standards Mapping - FIPS200 SI
[10] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data
[11] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-10 Information Input Validation (P1)
[12] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-10 Information Input Validation
[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.2.4 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.5 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.8 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)
[14] Standards Mapping - OWASP Mobile 2014 M1 Weak Server Side Controls
[15] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation
[16] Standards Mapping - OWASP Top 10 2004 A6 Injection Flaws
[17] Standards Mapping - OWASP Top 10 2007 A2 Injection Flaws
[18] Standards Mapping - OWASP Top 10 2010 A1 Injection
[19] Standards Mapping - OWASP Top 10 2013 A1 Injection
[20] Standards Mapping - OWASP Top 10 2017 A1 Injection
[21] Standards Mapping - OWASP Top 10 2021 A03 Injection
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.6
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.2
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.1
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.1
[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.1
[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.1
[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.1
[29] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4
[30] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4
[31] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection
[32] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation
[33] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation, Control Objective C.3.2 - Web Software Attack Mitigation
[34] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 116
[35] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3570 CAT I
[36] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3570 CAT I
[37] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3570 CAT I
[38] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3570 CAT I
[39] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3570 CAT I
[40] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3570 CAT I
[41] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3570 CAT I
[42] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002560 CAT I
[43] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002560 CAT I
[44] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002560 CAT I
[45] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002560 CAT I
[46] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002560 CAT I
[47] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002560 CAT I
[48] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002560 CAT I
[49] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002560 CAT I
[50] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002560 CAT I
[51] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002560 CAT I
[52] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002560 CAT I
[53] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002560 CAT I
[54] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002560 CAT I
[55] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[56] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[57] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)
desc.dataflow.javascript.server_side_template_injection
Abstract
User-controlled data is used as a template engine's template, allowing attackers to access the template context and in some cases inject and run arbitrary code on the application server.
Explanation
Template engines are used to render content using dynamic data. This context data is normally controlled by the user and formatted by the template to generate web pages, emails, and the like. Template engines allow powerful language expressions to be used in templates in order to render dynamic content, by processing the context data with code constructs such as conditionals, loops, etc. If an attacker can control the template to be rendered, they can inject expressions that expose context data or even run arbitrary commands on the server.
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered using the
Example 1: The following example shows how a template is retrieved from an HTTP request and rendered using the
Jinja2 template engine.
from django.http import HttpResponse
from jinja2 import Template as Jinja2_Template
from jinja2 import Environment, DictLoader, escape
def process_request(request):
# Load the template
template = request.GET['template']
t = Jinja2_Template(template)
name = source(request.GET['name'])
# Render the template with the context data
html = t.render(name=escape(name))
return HttpResponse(html)
Example 1 uses Jinja2 as the template engine. For that engine, an attacker could submit the following template to read arbitrary files from the server:Example 2: The following example shows how a template is retrieved from an HTTP request and rendered using the
template={{''.__class__.__mro__[2].__subclasses__()[40]('/etc/passwd').read()}}
Django template engine.
from django.http import HttpResponse
from django.template import Template, Context, Engine
def process_request(request):
# Load the template
template = source(request.GET['template'])
t = Template(template)
user = {"name": "John", "secret":getToken()}
ctx = Context(locals())
html = t.render(ctx)
return HttpResponse(html)
Example 2 uses Django as the template engine. For that engine, an attacker will not be able to execute arbitrary commands, but they will be able to access all the objects in the template context. In this example, a secret token is available in the context and could be leaked by the attacker.References
[1] Server-Side Template Injection: RCE for the modern webapp BlackHat
[2] Standards Mapping - Common Weakness Enumeration CWE ID 95
[3] Standards Mapping - Common Weakness Enumeration Top 25 2019 [18] CWE ID 094
[4] Standards Mapping - Common Weakness Enumeration Top 25 2020 [17] CWE ID 094
[5] Standards Mapping - Common Weakness Enumeration Top 25 2022 [25] CWE ID 094
[6] Standards Mapping - Common Weakness Enumeration Top 25 2023 [23] CWE ID 094
[7] Standards Mapping - Common Weakness Enumeration Top 25 2024 [11] CWE ID 094
[8] Standards Mapping - DISA Control Correlation Identifier Version 2 CCI-002754
[9] Standards Mapping - FIPS200 SI
[10] Standards Mapping - General Data Protection Regulation (GDPR) Indirect Access to Sensitive Data
[11] Standards Mapping - NIST Special Publication 800-53 Revision 4 SI-10 Information Input Validation (P1)
[12] Standards Mapping - NIST Special Publication 800-53 Revision 5 SI-10 Information Input Validation
[13] Standards Mapping - OWASP Application Security Verification Standard 4.0 5.2.4 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.5 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.2.8 Sanitization and Sandboxing Requirements (L1 L2 L3), 5.3.6 Output Encoding and Injection Prevention Requirements (L1 L2 L3)
[14] Standards Mapping - OWASP Mobile 2014 M1 Weak Server Side Controls
[15] Standards Mapping - OWASP Mobile 2024 M4 Insufficient Input/Output Validation
[16] Standards Mapping - OWASP Top 10 2004 A6 Injection Flaws
[17] Standards Mapping - OWASP Top 10 2007 A2 Injection Flaws
[18] Standards Mapping - OWASP Top 10 2010 A1 Injection
[19] Standards Mapping - OWASP Top 10 2013 A1 Injection
[20] Standards Mapping - OWASP Top 10 2017 A1 Injection
[21] Standards Mapping - OWASP Top 10 2021 A03 Injection
[22] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 Requirement 6.5.6
[23] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 Requirement 6.3.1.1, Requirement 6.5.2
[24] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 Requirement 6.5.1
[25] Standards Mapping - Payment Card Industry Data Security Standard Version 3.0 Requirement 6.5.1
[26] Standards Mapping - Payment Card Industry Data Security Standard Version 3.1 Requirement 6.5.1
[27] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2 Requirement 6.5.1
[28] Standards Mapping - Payment Card Industry Data Security Standard Version 3.2.1 Requirement 6.5.1
[29] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0 Requirement 6.2.4
[30] Standards Mapping - Payment Card Industry Data Security Standard Version 4.0.1 Requirement 6.2.4
[31] Standards Mapping - Payment Card Industry Software Security Framework 1.0 Control Objective 4.2 - Critical Asset Protection
[32] Standards Mapping - Payment Card Industry Software Security Framework 1.1 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation
[33] Standards Mapping - Payment Card Industry Software Security Framework 1.2 Control Objective 4.2 - Critical Asset Protection, Control Objective B.3.1 - Terminal Software Attack Mitigation, Control Objective B.3.1.1 - Terminal Software Attack Mitigation, Control Objective C.3.2 - Web Software Attack Mitigation
[34] Standards Mapping - SANS Top 25 2009 Insecure Interaction - CWE ID 116
[35] Standards Mapping - Security Technical Implementation Guide Version 3.1 APP3510 CAT I, APP3570 CAT I
[36] Standards Mapping - Security Technical Implementation Guide Version 3.4 APP3510 CAT I, APP3570 CAT I
[37] Standards Mapping - Security Technical Implementation Guide Version 3.5 APP3510 CAT I, APP3570 CAT I
[38] Standards Mapping - Security Technical Implementation Guide Version 3.6 APP3510 CAT I, APP3570 CAT I
[39] Standards Mapping - Security Technical Implementation Guide Version 3.7 APP3510 CAT I, APP3570 CAT I
[40] Standards Mapping - Security Technical Implementation Guide Version 3.9 APP3510 CAT I, APP3570 CAT I
[41] Standards Mapping - Security Technical Implementation Guide Version 3.10 APP3510 CAT I, APP3570 CAT I
[42] Standards Mapping - Security Technical Implementation Guide Version 4.2 APSC-DV-002560 CAT I
[43] Standards Mapping - Security Technical Implementation Guide Version 4.3 APSC-DV-002560 CAT I
[44] Standards Mapping - Security Technical Implementation Guide Version 4.4 APSC-DV-002560 CAT I
[45] Standards Mapping - Security Technical Implementation Guide Version 4.5 APSC-DV-002560 CAT I
[46] Standards Mapping - Security Technical Implementation Guide Version 4.6 APSC-DV-002560 CAT I
[47] Standards Mapping - Security Technical Implementation Guide Version 4.7 APSC-DV-002560 CAT I
[48] Standards Mapping - Security Technical Implementation Guide Version 4.8 APSC-DV-002560 CAT I
[49] Standards Mapping - Security Technical Implementation Guide Version 4.9 APSC-DV-002560 CAT I
[50] Standards Mapping - Security Technical Implementation Guide Version 4.10 APSC-DV-002560 CAT I
[51] Standards Mapping - Security Technical Implementation Guide Version 4.11 APSC-DV-002560 CAT I
[52] Standards Mapping - Security Technical Implementation Guide Version 4.1 APSC-DV-002560 CAT I
[53] Standards Mapping - Security Technical Implementation Guide Version 5.1 APSC-DV-002560 CAT I
[54] Standards Mapping - Security Technical Implementation Guide Version 5.2 APSC-DV-002560 CAT I
[55] Standards Mapping - Security Technical Implementation Guide Version 5.3 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[56] Standards Mapping - Security Technical Implementation Guide Version 6.1 APSC-DV-002530 CAT II, APSC-DV-002560 CAT I
[57] Standards Mapping - Web Application Security Consortium Version 2.00 Improper Input Handling (WASC-20)
desc.dataflow.python.server_side_template_injection