ed0e1e4d44
1979 changes to exploits/shellcodes Couchdb 1.5.0 - 'uuids' Denial of Service Apache CouchDB 1.5.0 - 'uuids' Denial of Service Beyond Remote 2.2.5.3 - Denial of Service (PoC) udisks2 2.8.0 - Denial of Service (PoC) Termite 3.4 - Denial of Service (PoC) SoftX FTP Client 3.3 - Denial of Service (PoC) Silverstripe 2.3.5 - Cross-Site Request Forgery / Open redirection SilverStripe CMS 2.3.5 - Cross-Site Request Forgery / Open Redirection Silverstripe CMS 3.0.2 - Multiple Vulnerabilities SilverStripe CMS 3.0.2 - Multiple Vulnerabilities Silverstripe CMS 2.4 - File Renaming Security Bypass SilverStripe CMS 2.4 - File Renaming Security Bypass Silverstripe CMS 2.4.5 - Multiple Cross-Site Scripting Vulnerabilities SilverStripe CMS 2.4.5 - Multiple Cross-Site Scripting Vulnerabilities Silverstripe CMS 2.4.7 - 'install.php' PHP Code Injection SilverStripe CMS 2.4.7 - 'install.php' PHP Code Injection Silverstripe Pixlr Image Editor - 'upload.php' Arbitrary File Upload SilverStripe CMS Pixlr Image Editor - 'upload.php' Arbitrary File Upload Silverstripe CMS 2.4.x - 'BackURL' Open Redirection SilverStripe CMS 2.4.x - 'BackURL' Open Redirection Silverstripe CMS - 'MemberLoginForm.php' Information Disclosure SilverStripe CMS - 'MemberLoginForm.php' Information Disclosure Silverstripe CMS - Multiple HTML Injection Vulnerabilities SilverStripe CMS - Multiple HTML Injection Vulnerabilities Apache CouchDB 1.7.0 and 2.x before 2.1.1 - Remote Privilege Escalation Apache CouchDB 1.7.0 / 2.x < 2.1.1 - Remote Privilege Escalation Monstra CMS before 3.0.4 - Cross-Site Scripting Monstra CMS < 3.0.4 - Cross-Site Scripting (2) Monstra CMS < 3.0.4 - Cross-Site Scripting Monstra CMS < 3.0.4 - Cross-Site Scripting (1) Navigate CMS 2.8 - Cross-Site Scripting Collectric CMU 1.0 - 'lang' SQL injection Joomla! Component CW Article Attachments 1.0.6 - 'id' SQL Injection LG SuperSign EZ CMS 2.5 - Remote Code Execution MyBB Visual Editor 1.8.18 - Cross-Site Scripting Joomla! Component AMGallery 1.2.3 - 'filter_category_id' SQL Injection Joomla! Component Micro Deal Factory 2.4.0 - 'id' SQL Injection RICOH Aficio MP 301 Printer - Cross-Site Scripting Joomla! Component Auction Factory 4.5.5 - 'filter_order' SQL Injection RICOH MP C6003 Printer - Cross-Site Scripting Linux/ARM - Egghunter (PWN!) + execve(_/bin/sh__ NULL_ NULL) Shellcode (28 Bytes) Linux/ARM - sigaction() Based Egghunter (PWN!) + execve(_/bin/sh__ NULL_ NULL) Shellcode (52 Bytes)
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Source: https://code.google.com/p/google-security-research/issues/detail?id=547
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If IExternalizable.writeExternal is overridden with a value that is not a function, Flash assumes it is a function even though it is not one. This leads to execution of a 'method' outside of the ActionScript object's ActionScript vtable, leading to memory corruption.
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A sample swf is attached. ActionScript code is also attached, but it does not compile to the needed to swf. To get the PoC, decompress the swf using flasm -x myswf, and then search for "triteExternal" and change it to "writeExternal".
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This bug is in the AVM serializer (http://hg.mozilla.org/tamarin-redux/file/5571cf86fc68/core/AvmSerializer.cpp), and is type confusion when calling the method writeExternal, which is implemented when a class extends IExternalizable (http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/utils/IExternalizable.html). The method is resolved on line 1437 of AvmSerializer.cpp by calling toplevel->getBinding, which does not guarantee that the binding is a method binding. It then gets cast to a method on line 773 and called, which is type confusion.
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One challenge with the bug is actually creating a SWF which can hit this code, as usually overriding a defined method will lead to an illegal override exception. The 0-day author did this differently than I did. The code where all class properties (methods, internal classes, variables, etc.) are resolved is in http://hg.mozilla.org/tamarin-redux/file/5571cf86fc68/core/Traits.cpp. You can see on line 813 that a check that no two properties of a class have the same name is commented out due to some legitimate SWFs doing that. This means that a SWF can have a variable with the same name as a method (overriding a method with less restrictive method is still illegal), which is how my PoC overrode the method. The 0-day did something slightly different, it put the redefinition of writeExternal in a different public namespace than the original definition of writeExternal. This has the benefit that the ActionScript will compile and hit the bug without modification.
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Proof of Concept:
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https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/38490.zip |