Messing with binary formats (live)
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Live version of my slide deck. Full version http://www.slideshare.net/ange4771/messing-with-binary-formats
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Messing with binary formats (live)
- 1. Messing with binary formats Ange Albertini 2013/09/13 London, England
- 10. MZ ?
- 26. Structure 1. start ○ PE Signature ■ %PDF + fake obj start ■ HTML comment start 2. next ○ PE (next) ○ HTML ○ PDF (next) 3. bottom ○ ZIP
- 39. %PDF***** 1 0 obj << /Size 2 /W[[]1/] /Root 1 0 R /Pages<< /Kids[<< /Contents<<>> stream BT{99 Tf{Td(Inlined PDF)' endstream >>] >> >> stream * endstream startxref%*******
- 40. %PDF-1.1 1 0 obj << % /Type /Catalog ... >> endobj 2 0 obj << /Type /Pages ... >> endobj 3 0 obj << /Type /Page /Resources << /Font << /F1 << /Type /Font /Subtype /Type1 ... >> >> >> >> endobj 4 0 obj << /Length 47>> stream ... xref 01 0000000000 65535 f 0000000010 00000 n ...
- 42. DEMO
- 44. 10.1.4 10.1.5
- 52. Weaknesses ● evasion ○ filters → exfiltration ○ same origin policy ○ detection ■ ex: clean PE but malicious PDF/HTML/... ■ exhaust checks ■ pretend to be corrupt ● DoS
- 53. Conclusion
- 54. Conclusion ● type confusion is bad ○ succinct docs too ○ lazy softwares as well ● go beyond the specs ○ Adobe: good ● suggestions ○ more extensions checks ○ isolate downloaded files ○ enforce magic signature at offset 0
- 55. thank YOU ! Questions ?
- 57. Bonus