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Null pointer dereference – new security bug for OpenSSL

ftp.openbsd.org

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Re: Null pointer dereference – new security bug for OpenSSL

#13
Good to note that this was found with KLEE[1]. KLEE is a good for symbolic execution of code and is very cool[2].

This only triggers a crash if you use RELEASE_BUFFERS (not the default) and a warning alert is written when the socket buffer is full. About the only case where a warning alert is generated is when a client attempts a renegotiation without the renegotiation extension (unless insecure renegotiation is allowed by the app). I've not been able to trigger the bug in a test because code generally stops reading once the socket buffer is full so you need the application to exactly fill the socket buffer (so that it doesn't get EAGAIN), then a warning alert can just exceed it.

[1] http://marc.info/?l=openssl-dev&m=139809493725682&w=2 [2] http://klee.github.io/klee/

Re: Null pointer dereference – new security bug for OpenSSL

#14

Like I said in the other thread on 5.5, make sure you update for the patches. http://www.openbsd.org/errata55.html This one is listed on that page (bottom 005: SECURITY FIX: May 1, 2014).

I think they are sending out e-mails about new patches.

Re: Null pointer dereference – new security bug for OpenSSL

#17

Is it me or should code that has to be secure be written in more manage languages to prevent these mistake ? (But managed languages probably have other security issues I don't know about ?)

Managed languages is one way to go, but they are not really appropriate for performance critical libraries like OpenSSL in my book. You can get safety without being managed in modern languages if the compiler does the safety proving for you (e.g. rustlang).

Re: Null pointer dereference – new security bug for OpenSSL

#18

Are there any write ups for this yet? I can't find a CVE or anything on this one. No word from OpenSSL yet either.

This shouldn't be exploitable on modern linux machines due to https://wiki.debian.org/mmap_min_addr

Who knows for embedded devices.

Re: Null pointer dereference – new security bug for OpenSSL

#19

Is it me or should code that has to be secure be written in more manage languages to prevent these mistake ? (But managed languages probably have other security issues I don't know about ?)

Managed languages are very susceptible to timing attacks.

Re: Null pointer dereference – new security bug for OpenSSL

#20

Is it me or should code that has to be secure be written in more manage languages to prevent these mistake ? (But managed languages probably have other security issues I don't know about ?)

If OpenSSL was written in a managed language, someone would need it in an environment a managed language wasn't suitable for, and end up porting it to C.
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