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Senast redigerad av Enterprise 2024-04-07 kl. 09:12.
Senast redigerad av Enterprise 2024-04-07 kl. 09:12.
Citat:
Har du slutat slå din fru?
Jag har inte behandlat den generella, övergripande, och hypotetiska digniteten - jag har enbart påpekat att vissa här står som några jävla mähän och låtsas som att tillvägagångsättet inte borde triggat några larm? Hade det funnits ett uns av SecOps i närheten av det här projektet så hade inte "någon tjomme" kunnat vandra in på detta sättet.
Och.. häng med här..
Att "någon tjomme" med tre eller fyra epostadresser kan skapa sig en falsk urkund som inom två års tid kan bli upstream repo maintainer för ett projekt som paketerar source tarballs som absorberas direkt in i dists [som premierat implementationen för en exotisk systemd feature -] som i sin tur utgör hälften till två tredjedelar av världens serverrum - däri ligger nyheten och hela problemet. Resten är sensationellt mög.
Jag behöver inte söka, får skiten matad till mig via de maillistor dina källor refererar.
Senaste btw:
Citat:
https://twitter.com/bl4sty/status/1776691497506623562
the xz sshd backdoor rabbithole goes quite a bit deeper. I was just able to trigger some harder to reach functionality of the backdoor. there's still more to explore.. 1/n
it requires sending a properly crafted command to the RSA_public_decrypt hook, which will then install another for the `mm_answer_keyallowed` sshd function. subsequently you offer N more fake ssh-rsa pubkeys which are crafted in a special way to chunk together .. 2/n
a "magic buffer" which contains more backdoor commands, this buffer also has two additional ed448 signatures. which like the ones for the RSA_public_decrypt portion of the backdoor are salted with the SHA256 digest of the hostkey
the final signature also takes into account the session_id (0x20 bytes) that is derived during the initial key exchange (KEX) for the SSH session. my current PoC implementation uses a heavily monkey patched paramiko (ssh client) library to achieve this
(that conclusion is based on the fact that one of the mm_answer_keyallowed backdoor commands also hooks mm_answer_keyverify, eventually)
whoever designed this stuff had to take a deep dive into openSSH(d) internals (and so did I for the past couple of days, oof) .. hats off, once again
it requires sending a properly crafted command to the RSA_public_decrypt hook, which will then install another for the `mm_answer_keyallowed` sshd function. subsequently you offer N more fake ssh-rsa pubkeys which are crafted in a special way to chunk together .. 2/n
a "magic buffer" which contains more backdoor commands, this buffer also has two additional ed448 signatures. which like the ones for the RSA_public_decrypt portion of the backdoor are salted with the SHA256 digest of the hostkey
the final signature also takes into account the session_id (0x20 bytes) that is derived during the initial key exchange (KEX) for the SSH session. my current PoC implementation uses a heavily monkey patched paramiko (ssh client) library to achieve this
(that conclusion is based on the fact that one of the mm_answer_keyallowed backdoor commands also hooks mm_answer_keyverify, eventually)
whoever designed this stuff had to take a deep dive into openSSH(d) internals (and so did I for the past couple of days, oof) .. hats off, once again
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Senast redigerad av Ehandel 2024-04-07 kl. 19:29.
Senast redigerad av Ehandel 2024-04-07 kl. 19:29.
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