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使用Perl XML::Simple解析带命名空间的xml

xmlperlparsing
3

大家好，我真的需要帮助。我的最终目标是使用Perl读取一个XML文件，并将其插入到数据库中以跟踪CVE。在这个阶段，如果我能够在代码中引用XML文件中的变量，我相信我可以将它插入到数据库中。现在，我只是想将其打印到屏幕上，但却无法实现。

以下是我的简单代码和XML文件。

希望有人能指导我。

-- Perl代码开始 --

#!/usr/bin/perl

# use module
use XML::Simple;
use Data::Dumper;

# create object
xml = new XML::Simple (KeyAttr=>[]);

# read XML file
#$data = $xml->XMLin("tms.xml");

# print output - used this to see if it was even reading it
#print Dumper($data);

# access XML data
print "Here is the BugTrackID: $data->{'x:BugTraqID'}\n";

--end of perl code---

--start of xml--

<?xml version="1.0" encoding="us-ascii"?>
<Alerts xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:alerts.symantec.com https://alerts.symantec.com/vulalert.xsd">
<x:AlertDocument xmlns:x="urn:alerts.symantec.com" AlertStatusID="57982" Type="1" DetailLevel="25" Language="1">
<x:BugTraqID>57982</x:BugTraqID>
<x:Title>Sonar Multiple Cross Site Scripting Vulnerabilities</x:Title>
<x:StatusID>1</x:StatusID>
<x:CVE>CVE-MAP-NOMATCH</x:CVE>
<x:Published>Feb 12 2013</x:Published>
<x:LastUpdated>2013-02-15T19:03:48</x:LastUpdated>
<x:Remote>Yes</x:Remote>
<x:Local>No</x:Local>
<x:Credibility>Single Source</x:Credibility>
<x:Classification>Input Validation Error</x:Classification>
<x:Availability>User Initiated</x:Availability>
<x:Ease>Exploit Available</x:Ease>
<x:Authentication>Not Required</x:Authentication>
<x:CVSS2_BaseScore>5.8</x:CVSS2_BaseScore>
<x:CVSS2_TemporalScore>5</x:CVSS2_TemporalScore>
<x:CVSS2_BaseVector>AV:N/AC:M/Au:N/C:P/I:P/A:N</x:CVSS2_BaseVector>
<x:CVSS2_TemporalVector>E:F/RL:U/RC:UC</x:CVSS2_TemporalVector>
<x:CVSS1_BaseScore>3.7</x:CVSS1_BaseScore>
<x:CVSS1_TemporalScore>3.2</x:CVSS1_TemporalScore>
<x:NVD_CVSS2_BaseScore>4.3</x:NVD_CVSS2_BaseScore>
<x:NVD_CVSS2_ComponentString>AV:N/AC:M/Au:N/C:N/I:P/A:N</x:NVD_CVSS2_ComponentString>
<x:ImpactRating>4</x:ImpactRating>
<x:Severity>6.1</x:Severity>
<x:EaseofExploit>8</x:EaseofExploit>
<x:UrgencyRating>6.1</x:UrgencyRating>
<x:LastChange>Initial analysis.</x:LastChange>
<x:VulnerableSystems>
  <x:VulnerableSystem>
    <x:Title><![CDATA[SonarSource Sonar 3.4.1 cpe:/a:sonarsource:sonar:3.4.1 SYMC]]></x:Title>
  </x:VulnerableSystem>
</x:VulnerableSystems>
<x:ShortSummary><![CDATA[Sonar is prone to multiple cross-site scripting vulnerabilities.]]></x:ShortSummary>
<x:Impact>An attacker may leverage these issues to   execute arbitrary script code in the browser of an unsuspecting user in   the context of the affected site. This may allow the attacker to steal   cookie-based authentication credentials and launch other attacks.</x:Impact>
<x:TechnicalDescription><![CDATA[Sonar is the open source platform for code quality inspection.         

The application is prone to multiple  cross-site scripting vulnerabilities because it fails to sanitize  user-supplied input submitted to the following scripts and parameters:     

&apos;index.php  &apos; : &apos;search&apos;,   &apos;assignee_login&apos;,      
&apos;author_login&apos;     
&apos;sources.php&apos; :  &apos;resource&apos;     

An attacker may leverage these issues to  execute arbitrary script code in the browser  of an unsuspecting user in  the context of the affected site. This may allow the attacker to steal  cookie-based authentication credentials and launch other attacks.                                                 

Sonar 3.4.1 is vulnerable; other versions may also be affected.]]>  
</x:TechnicalDescription>
<x:AttackScenario><![CDATA[1. An attacker scans for and locates a site running the affected application.      

2. The attacker crafts a URI link that includes malicious script code designed to leverage one of these issues.      

3. The attacker uses email or other means to distribute the malicious link and entices an unsuspecting user to follow it.      

4. When the user follows the link, the attacker-specified script code runs in their browser in the context of the affected site.       

A successful exploit may let the attacker steal cookie-based authentication credentials and launch other attacks.]]></x:AttackScenario>
<x:Exploit><![CDATA[Attackers can exploit these issues by enticing an unsuspecting victim into following a malicious URI.         

The following example URIs are available: 

http://www.example.com/dependencies/index?   search="&amp;gt;&amp;lt;script&amp;gt;alert(/devilteam.pl/)&amp;lt;/script&amp;gt; 

http://www.example.com/dashboard/index/41730? did=4&amp;amp;period=3"&amp;gt;&amp;lt;script&amp;gt;alert(/devilteam.pl/)&amp;lt;/script&am p;gt; 

http://www.example.com/reviews/index?review_id=&amp;amp;statuses[]=OPEN&amp;amp;statuses[]=REOPENED&amp;amp;severities[]=&amp;amp;projects[]=&amp;amp;amp;author_login=&amp;amp;assignee_login="&amp;gt;&amp;lt;script&amp;gt;alert(/devilteam.pl/)&amp;lt;/script&amp;gt;&amp;amp;false_positives=without&amp;amp;sort=&amp;amp;asc=false&amp;amp;commit=Search 

http://www.example.com/reviews/index?review_id=&amp;amp;statuses[]=OPEN&amp;amp;statuses[]=REOPENED&amp;amp;severities[]=&amp;amp;projects[]=&amp;amp;amp;author_login="&amp;gt;&amp;lt;script&amp;gt;alert(/devilteam.pl/)&amp;lt;/script&amp;gt;&amp;amp;assignee_login=&amp;amp;false_positives=without&amp;amp;sort=&amp;amp;asc=false&amp;amp;commit=Search 

http://www.example.com/api/sources?resource=&amp;lt;script&amp;gt;alert(/devilteam.pl/)&amp;lt;/script&amp;gt;&amp;amp;format=txt

]]></x:Exploit>
<x:MitigatingStrategies>
  <x:MitigatingStrategy>
    <x:Title><![CDATA[Block external access at the network boundary, unless external parties require service.]]></x:Title>
    <x:Description><![CDATA[If global access isn&apos;t needed, filter access to the affected computer at the network boundary. Restricting access to only trusted computers and networks might greatly reduce the likelihood of a successful exploit.]]></x:Description>
  </x:MitigatingStrategy>
  <x:MitigatingStrategy>
    <x:Title><![CDATA[Run all software as a nonprivileged user with minimal access rights.]]></x:Title>
    <x:Description><![CDATA[Attackers may successfully exploit client flaws in the browser through cross-site scripting vulnerabilities. When possible, run client software as regular user accounts with limited access to system resources. This may limit the immediate consequences of client-side vulnerabilities. ]]></x:Description>
  </x:MitigatingStrategy>
  <x:MitigatingStrategy>
    <x:Title><![CDATA[Do not follow links provided by unknown or untrusted sources.]]></x:Title>
    <x:Description><![CDATA[Web users should be cautious about following links to websites that are provided by unfamiliar or suspicious sources. Filtering HTML from emails may help remove a possible vector for transmitting malicious links to users. ]]></x:Description>
  </x:MitigatingStrategy>
  <x:MitigatingStrategy>
    <x:Title><![CDATA[Set web browser security to disable the execution of script code or active content.]]></x:Title>
    <x:Description><![CDATA[Since exploiting cross-site scripting issues often requires malicious script code to run in browsers, consider disabling script code and active content support within a client browser as a way to prevent a successful exploit. Note that this mitigation tactic might adversely affect legitimate sites that rely on the execution of browser-based script code. ]]></x:Description>
  </x:MitigatingStrategy>
</x:MitigatingStrategies>
<x:Solutions>
  <x:Workaround><![CDATA[Workaround
]]></x:Workaround>
  <x:Solution><![CDATA[Currently, we are not aware of any vendor-supplied patches. If you feel we are in error or are aware of more recent information, please mail us at: vuldb@securityfocus.com.]]></x:Solution>
</x:Solutions>
<x:Credit>DevilTeam</x:Credit>
<x:ChangeLogs>
  <x:ChangeLog>
    <x:Title><![CDATA[2013.02.15: Initial analysis.]]></x:Title>
  </x:ChangeLog>
</x:ChangeLogs>
<x:References>
  <x:Reference>
    <x:Title><![CDATA[Web Page:Sonar Homepage (SonarSource) SonarSource]]></x:Title>
    <x:URL><![CDATA[http://www.sonarsource.com/products/software/sonar/]]></x:URL>
    <x:Description><![CDATA[http://www.sonarsource.com/products/software/sonar/]]></x:Description>
  </x:Reference>
  <x:Reference>
    <x:Title><![CDATA[Web Page:Sonar v.3.4.1 =&amp;gt; XSS (CWE-79) (DevilTeam) DevilTeam]]></x:Title>
    <x:URL><![CDATA[http://cxsecurity.org/issue/WLB-2013020088]]></x:URL>
    <x:Description><![CDATA[http://cxsecurity.org/issue/WLB-2013020088]]></x:Description>
  </x:Reference>
</x:References>
<x:URL>https://alerts.symantec.com/loaddocument.aspx?GUID=cffd18f0-7b75-4c6a-adc0-74f480808fff</x:URL>
<x:OVALDefinitions />
</x:AlertDocument>
</Alerts>

--XML 结束--

你遇到了什么问题？ - ikegami
你提到了命名空间。XML::Simple 对于命名空间和前缀有所了解。它只是假设前缀是节点名称的一部分。"XML::Simple 是你可以使用的最复杂的 XML 解析器。" - ikegami
我无法输出任何值。具体而言，我只是尝试从xml文件中打印bugtraqid值。它返回null。 - J. S.
有没有更好的选择？我真正需要做的就是读取文件并将其中一些标签存储在数据库中。 - J. S.
我更喜欢使用XML::LibXML库。请看我的更新。 - ikegami
2个回答
4

你是否在寻找$data->{'x:AlertDocument'}{'x:BugTraqID'}？

我更喜欢使用XML::LibXML。以下代码可以适用于任何文档中使用的前缀，无论是否有前缀（你不应该关心文档中使用了哪个前缀）。

#!/usr/bin/perl

use strict;
use warnings;

use XML::LibXML               qw( );
use XML::LibXML::XPathContext qw( );

my $parser = XML::LibXML->new();
my $doc = $parser->parse_file("tms.xml");

my $xpc = XML::LibXML::XPathContext->new($doc);
$xpc->registerNs(x => 'urn:alerts.symantec.com');

for my $alert_doc ($xpc->findnodes('/Alerts/x:AlertDocument')) {
   my ($bug_traq_id) = $xpc->findnodes('x:BugTraqID', $alert_doc);
   print $bug_traq_id->textContent(), "\n";
}
或许你的XML::Simple正在使用一个有问题的XML解析器？ XML::Simple实际上并不是一个解析器；它只是一个许多解析器中的一个前端。 - ikegami
哦，是的，我不得不将 xml 更改为 $xml，并将 #$data 更改为 $data。你发布的内容甚至无法编译。 - ikegami
你在使用xml::parser吗？ - J. S.
啊，是的！你懂了。我实际上把我的输入文件注释掉了！天哪，这太尴尬了。但更重要的是，你原来的答案是正确的。我需要阅读关于 'x:AlertDocument' 的资料并弄清楚它的作用。 - J. S.
AlertDocument是BugTraqID的父节点，就像Alerts是AlertDocument的父节点一样。 - ikegami
显示剩余4条评论
-1

你的XML没有目标命名空间。这不是问题，但你必须考虑到它。

你可以指定XML::Simple将使用哪个解析器。

这里有一个代码示例，使用XML::Simple可以得到你期望的结果。

tvnshack$ ./a.pl 
Trying bugtrack.xml ... bugtrack.xml is indeed valid
 BugTrackID is: 57982

代码如下...可以根据您的喜好进行调整（它基于我在生产中使用的一些实时代码）。

#!/opt/perl/bin/perl -w

use strict;
use XML::Simple qw(:strict);
use Data::Dumper;

# Supported namespaces
my $nspcBUGT = 'urn:alerts.symantec.com';
my $parsingfailed = 0;
my $XMLdata;

my $XMLfname = 'bugtrack.xml';

  print STDOUT "Trying $XMLfname ... ";

  $XML::Simple::PREFERRED_PARSER = 'XML::SAX::Expat';
  my $simpleCstr = XML::Simple->new(
    Cache => [ 'memshare' ],
    KeyAttr => [],
    ForceArray => 1,
    KeepRoot => 1,
    ContentKey => 'value',
    NSExpand => 1,
    NormaliseSpace => 1);
  eval {
    $parsingfailed++;
    # if the parsing fails, the module will terminate the process abruptly. 
    $XMLdata = $simpleCstr->XMLin($XMLfname);
    # This line of code will not be executed, leaving $parsingfailed>0.
    $parsingfailed = 0;
  };
  if ( $parsingfailed > 0) {
    print STDERR "Error: That XML file <$XMLfname> can not be read, does not exist or is not a valid XML file (possible wrong namespace too).\n";
  } else {
    if (defined($XMLdata->{"Alerts"})) {
      print STDOUT "$XMLfname is indeed valid\n";
      print STDOUT " BugTrackID is: " . $XMLdata->{'Alerts'}->[0]->{"{$nspcBUGT}AlertDocument"}->[0]->{"{$nspcBUGT}BugTraqID"}->[0] . "\n";
      #  print Dumper($XMLdata) . "\n";
    }
  }

__END__
我想知道谁以及为什么对这个贡献投了负面票，并且希望能讨论一下。我有长期生产环境运行代码的经验，并从实践中学习到了很多。我保证，任何不采取上述预防措施的人迟早会遇到问题。我可能是错误的，或者不够详尽。这需要讨论。 - TVNshack
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