CVE-2020-1337 – PrintDemon is dead, long live PrintDemon!

Banner Image by Sergio KalisiakTL; DR: I will explain, in details, how to trigger PrintDemon exploit and dissect how I’ve discovered a new 0-day; Microsoft Windows EoP CVE-2020-1337, a bypass of PrintDemon’s recent patch via a Junction Directory (TOCTOU).ContentsPrintDemon primer, how the exploit works?PrinterPort WritePrinter Shadow Job FileBinary Diffing CVE-2020-1048 Patch CVE-2020-1337 – A bypass of CVE-2020-1048’s patch Conclusion Affected Systems Disclosure TimelineAfter Yarden Shafir’s & Alex Ionescu’s posts (PrintDemon, FaxHell) and their call to action,...

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A tale of a kiosk escape: ‘Sricam CMS’ Stack Buffer Overflow

TL;DR: Shenzhen Sricctv Technology Sricam CMS (SricamPC.exe) <= v.1.0.0.53(4) and DeviceViewer (DeviceViewer.exe) <= v.3.10.12.0 (CVE-2019-11563) are affected by a local Stack Buffer Overflow. By creating a specially crafted "Username" and copying its value in the "User/mail" login field, an attacker will be able to gain arbitrary code execution in the context of the currently logged-in user.Please Note: by default, Sricam CMS requires elevation and runs in High Integrity mode; exploitation of the above software will result in a compromise...

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Tabletopia: from XSS to RCE

During this period of social isolation, a friend of mine proposed to play some online "board games". He proposed “Tabletopia”: a cool sandbox virtual table with more than 800 board games.Tabletopia is both accessible from its own website and from the Steam’s platform.While my friends decided to play from their browser, I’ve opted for the Steam version. We joined a room and started a game; at one point we were messing around with some in-game cards when , for...

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SLAE – Assignment #7: Custom Shellcode Crypter

Assignment #7: Custom Shellcode Crypter Seventh and last SLAE’s assignment requires to create a custom shellcode crypter.Since I had to implement an entire encryption schema both in python as an helper and in assembly as the main decryption routine, I've opted for something simple. I've chosen the Tiny Encryption Algorithm (TEA) as it does not require large IV or SBOX initialization vectors (adding a huge overhead to my shellcode's decoding routine), because it's tiny and not too complex to re-implement.As...

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SLAE – Assignment #6: Polymorphic Shellcode

Assignment #6: Polymorphic Shellcode Sixth SLAE’s assignment requires to create three different (polymorphic) shellcodes version starting from published Shell Storm's examples.I've decided to take this three in exam:http://shell-storm.org/shellcode/files/shellcode-752.php - linux/x86 execve ("/bin/sh") - 21 bytes http://shell-storm.org/shellcode/files/shellcode-624.php - linux/x86 setuid(0) + chmod("/etc/shadow",0666) - 37 bytes http://shell-storm.org/shellcode/files/shellcode-231.php - linux/x86 open cd-rom loop (follows "/dev/cdrom" symlink) - 39 bytesAs always, all the code is also available on GitHub.Stay updated, join VoidSec's Telegram Channel: https://t.me/voidsec_updates execve ("/bin/sh") Original: ; http://shell-storm.org/shellcode/files/shellcode-752.phpxor ecx, ecx mul ecx push ecx push 0x68732f2f ...

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