hohn/codeql
1
0
Fork 0
mirror of https://github.com/github/codeql.git synced 2026-04-30 19:26:02 +02:00
Code Issues Packages Projects Releases Wiki Activity

Improve qhelp

Browse Source
This commit is contained in:
jorgectf
2021-04-08 23:44:30 +02:00
parent 7296879bc9
commit 3c1ca72324
1 changed files with 44 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

66
python/ql/src/experimental/Security/CWE-090/LDAPInjection.qhelp
View File

@@ -1,28 +1,50 @@
<!DOCTYPE qhelp PUBLIC "-//Semmle//qhelp//EN" "qhelp.dtd">
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<overview>
<p>If an LDAP query is built by a not sanitized user-provided value, a user is likely to be able to run malicious LDAP queries.</p>
</overview>
<overview>
<p>If an LDAP query or DN is built using string concatenation or string formatting, and the
components of the concatenation include user input without any proper sanitization, a user
is likely to be able to run malicious LDAP queries.</p>
</overview>
<recommendation>
<p>In case user input must compose an LDAP query, it should be escaped in order to avoid a malicious user supplying special characters that change the actual purpose of the query. To do so, functions that ldap frameworks provide such as <code>escape_filter_chars</code> should be applied to that user input.
<recommendation>
<recommendation>
<p>If user input must be included in an LDAP query or DN, it should be escaped to
avoid a malicious user providing special characters that change the meaning
of the query. In Python2, user input should be escaped with <code>ldap.dn.escape_dn_chars</code>
or <code>ldap.filter.escape_filter_chars</code>, while in Python3, user input should be escaped with
<code>ldap3.utils.dn.escape_rdn</code> or <code>ldap3.utils.conv.escape_filter_chars</code>
depending on the component tainted by the user. A good practice is to escape filter characters
that could change the meaning of the query (https://tools.ietf.org/search/rfc4515#section-3).</p>
</recommendation>
<example>
<p>In the following examples, the code accepts both <code>username</code> and <code>dc</code> from the user,
which it then uses to build a LDAP query and DN.</p>
<references>
<li>
OWASP
<a href="https://owasp.org/www-community/attacks/LDAP_Injection">LDAP Injection</a>
</li>
<li>
SonarSource
<a href="https://rules.sonarsource.com/python/RSPEC-2078">RSPEC-2078</a>
</li>
<li>
Python
<a href="https://www.python-ldap.org/en/python-ldap-3.3.0/reference/ldap.html">LDAP Documentation</a>
</li>
</references>
<p>The first and the second example uses the unsanitized user input directly
in the search filter and DN for the LDAP query.
A malicious user could provide special characters to change the meaning of these
components, and search for a completely different set of values.</p>
<sample src="examples/example_bad1.js" />
<sample src="examples/example_bad2.js" />
<p>In the third and four example, the input provided by the user is sanitized before it is included in the search filter or DN.
This ensures the meaning of the query cannot be changed by a malicious user.</p>
<sample src="examples/example_good1.js" />
<sample src="examples/example_good2.js" />
</example>
<references>
<li>OWASP: <a href="https://cheatsheetseries.owasp.org/cheatsheets/LDAP_Injection_Prevention_Cheat_Sheet.html">LDAP Injection Prevention Cheat Sheet</a>.</li>
<li>OWASP: <a href="https://owasp.org/www-community/attacks/LDAP_Injection">LDAP Injection</a>.</li>
<li>SonarSource: <a href="https://rules.sonarsource.com/python/RSPEC-2078">RSPEC-2078</a>.</li>
<li>Python2: <a href="https://www.python-ldap.org/en/python-ldap-3.3.0/reference/ldap.html">LDAP Documentation</a>.</li>
<li>Python3: <a href="https://ldap3.readthedocs.io/en/latest/">LDAP Documentation</a>.</li>
<li>Wikipedia: <a href="https://en.wikipedia.org/wiki/LDAP_injection">LDAP injection</a>.</li>
<li>BlackHat: <a href="https://www.blackhat.com/presentations/bh-europe-08/Alonso-Parada/Whitepaper/bh-eu-08-alonso-parada-WP.pdf">LDAP Injection and Blind LDAP Injection</a>.</li>
<li>LDAP: <a href="https://ldap.com/2018/05/04/understanding-and-defending-against-ldap-injection-attacks/">Understanding and Defending Against LDAP Injection Attacks</a>.</li>
</references>
</qhelp>