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)
72 lines
No EOL
3.5 KiB
Text
72 lines
No EOL
3.5 KiB
Text
Source: https://code.google.com/p/google-security-research/issues/detail?id=525
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Fuzzing packed executables found the attached crash, it might be usable as an information leak as part of another bug, so filing as a low-risk bug. If I had to guess, I would say this is the ExeCryptor unpacker.
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(83c.fc0): Access violation - code c0000005 (first chance)
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First chance exceptions are reported before any exception handling.
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This exception may be expected and handled.
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eax=0b61f00c ebx=00030ff4 ecx=00000000 edx=00000000 esi=0409005c edi=00000000
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eip=15cc7e73 esp=0441ecf8 ebp=0441ef18 iopl=0 nv up ei pl nz ac pe cy
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010217
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15cc7e73 803c03e9 cmp byte ptr [ebx+eax],0E9h ds:002b:0b650000=??
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What is that code doing?
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0:021> u
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15cc7e73 803c03e9 cmp byte ptr [ebx+eax],0E9h
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15cc7e77 0f8596000000 jne 15cc7f13
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15cc7e7d 8b540301 mov edx,dword ptr [ebx+eax+1]
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15cc7e81 8d441a05 lea eax,[edx+ebx+5]
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15cc7e85 33c9 xor ecx,ecx
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15cc7e87 3d00100000 cmp eax,1000h
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15cc7e8c 0f9cc1 setl cl
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15cc7e8f 33d2 xor edx,edx
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That edx+ebx+5 gives it away, it's searching for a jmp opcode and trying to pull out the branch target.
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Why did it get lost? I'll put a breakpoint there and see where it goes wrong:
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0:021> bp @eip
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0:021> .restart
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Breakpoint 0 hit
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eax=0584f00c ebx=00000000 ecx=0497eb4c edx=00000000 esi=05a1005c edi=00000000
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eip=15cc7e73 esp=0497ebc4 ebp=0497ede4 iopl=0 nv up ei ng nz na po nc
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000282
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15cc7e73 803c03e9 cmp byte ptr [ebx+eax],0E9h ds:002b:0584f00c=00
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That looks fine, eax is the start of the buffer to search, and ebx is the index to look for a jmp opcode.
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0:024> t
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eax=0584f00c ebx=00000000 ecx=0497eb4c edx=00000000 esi=05a1005c edi=00000000
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eip=15cc7e77 esp=0497ebc4 ebp=0497ede4 iopl=0 nv up ei pl nz ac pe cy
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000217
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15cc7e77 0f8596000000 jne 15cc7f13 [br=1]
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0:024> t
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eax=0584f00c ebx=00000000 ecx=0497eb4c edx=00000000 esi=05a1005c edi=00000000
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eip=15cc7f13 esp=0497ebc4 ebp=0497ede4 iopl=0 nv up ei pl nz ac pe cy
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000217
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15cc7f13 43 inc ebx
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0:024> t
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eax=0584f00c ebx=00000001 ecx=0497eb4c edx=00000000 esi=05a1005c edi=00000000
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eip=15cc7f14 esp=0497ebc4 ebp=0497ede4 iopl=0 nv up ei pl nz na po cy
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000203
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15cc7f14 8d47fb lea eax,[edi-5]
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0:024> t
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eax=fffffffb ebx=00000001 ecx=0497eb4c edx=00000000 esi=05a1005c edi=00000000
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eip=15cc7f17 esp=0497ebc4 ebp=0497ede4 iopl=0 nv up ei pl nz na po cy
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cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00000203
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15cc7f17 3bd8 cmp ebx,eax
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Ah, that's the bug, it's wrapping past zero and never exiting. The code is probably doing:
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do {
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if (ptr[index] != JMP_OPCODE)
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index -= SIZEOF_JMP;
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} while (index != 0);
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That's a bug, because if index < SIZEOF_JMP, it will wrap and never exit. I would think it should decrement by 1 not sizeof(jmp) anyway, because jmps do not have to be aligned, but I don't know anything about ExeCryptor - maybe it makes sense.
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Proof of Concept:
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https://github.com/offensive-security/exploitdb-bin-sploits/raw/master/bin-sploits/38282.zip |