Forum: Ruby ruby 1.8.7 patchlevel 357 released

Hello all.


We have been releasing annual ruby versions for over a decade in
this season.  This is one for this year.  We have fixed several
bugs today.  One of them is to fix CVE-2011-4815 (a more detailed
situation about the issue is to follow this mail).  So everyone
who uses 1.8.7 should consider upgrading.

For details, please read the ChangeLog as usual.

ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.tar.gz
ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.tar.bz2
ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.zip

Checksums:

MD5(ruby-1.8.7-p357.tar.gz)= b2b8248ff5097cfd629f5b9768d1df82
SHA256(ruby-1.8.7-p357.tar.gz)= 
2fdcac4eb37b2eba1a4eef392a2922e07a9222fc86d781d92154d716434b962c
SIZE(ruby-1.8.7-p357.tar.gz)= 4895136

MD5(ruby-1.8.7-p357.tar.bz2)= 3abd9e2a29f756a0d30c7bfca578cdeb
SHA256(ruby-1.8.7-p357.tar.bz2)= 
5c64b63a597b4cb545887364e1fd1e0601a7aeb545e576e74a6d8e88a2765a37
SIZE(ruby-1.8.7-p357.tar.bz2)= 4208157

MD5(ruby-1.8.7-p357.zip)= 23efe7ba50458f8df691c7fa07ce0578
SHA256(ruby-1.8.7-p357.zip)= 
b7672524ecac77e7f4bdbbfa5521109a0ef514d22bc726bad073d83b6044d445
SIZE(ruby-1.8.7-p357.zip)= 5994841


Have a happy new year,

Subject:

Denial of service attack was found for Ruby's Hash algorithm

Impact:

This  is  something related  to  computational complexity.   Specially
crafted series of strings that intentionally collide their hash values
each other  was found.   With such sequences  an attacker can  issue a
denial  of  service attack  by,  for  instance,  giving them  as  POST
parameters of HTTP requests for your Rails application.

Detailed description:

The situation  is similar to the one  found for Perl in  2003.  In 1.8
series of Ruby, we use a deterministic hash function to hash a string.
Here the "deterministic"  means no other bits of  information than the
input string itself is involved to  generate a hash value.  So you can
precalculate a string's hash value beforehand.  By collecting a series
of strings  that have  the identical hash  value, an attacker  can let
ruby  process collide  bins  of hash  tables  (including `Hash`  class
instances).   Hash   tables'  amortized  O(1)   attribute  depends  on
uniformity  of distribution of  hash values.   By giving  such crafted
input, an attacker can let  hash tables work much slower than expected
(namely O(n2) to construct a n-elements table this case).

Affected versions:

- Ruby 1.8.7-p352 and all prior versions.

All Ruby 1.9 series are not  affected by this kind of attack.  They do
not share hash implementations with Ruby 1.8 series.

Solution:

Our  solution  is  to  scramble  the  string  hash  function  by  some
PRNG-generated random bits.  By doing so a string's hashed value is no
longer deterministic.   That is, a `String#hash`  result is consistent
only for current process lifetime and will generate a different number
for the next boot.  To break  this situation an attacker must create a
set of  strings which are robust  to this kind of  scrambling. This is
believed to be quite difficult.

Please upgrade to the latest version of ruby via my previous post.

http://mla.n-z.jp/?ruby-talk=391606

Notes:

* Bear  in  mind  that  the  solution _does_  _not_  _mean_  our  hash
  algorithm is  cryptographically secure.  To put it  simple, we fixed
  the  hash  table  but  we  didn't fix  `String#hash`  weakness.   An
  attacker could still exploit it once he / she got a pair of a string
  and its  hash value returned  from `String#hash`.  You  _must_ _not_
  disclose  `String#hash` outputs.   If you  need to  do  such things,
  consider using  secure hash algorithms instead.  Some  of them (such
  as SHA256) are provided in Ruby's standard library.

* For  those who  knows alternative  hash algorithms  inside  our code
  base: we  do not  support them (they  are disabled by  default).  By
  choosing them  we consider  you can read  C, and you  can understand
  what was wrong with the default  one.  Make sure that your choice is
  safe at your own risk.

Credit:

Credit  to  Alexander  Klink  <alexander.klink@nruns.com>  and  Julian
Waelde  <jwaelde@cdc.informatik.tu-darmstadt.de>  for  reporting  this
issue.

-----Messaggio originale-----
Da: Urabe Shyouhei [mailto:shyouhei@ruby-lang.org]
Inviato: mercoled 28 dicembre 2011 14:14
A: ruby-talk ML; ruby-list@ruby-lang.org
Oggetto: [ANN] ruby 1.8.7 patchlevel 357 released

Hello all.


We have been releasing annual ruby versions for over a decade in this
season.  This is one for this year.  We have fixed several bugs today. 
One
of them is to fix CVE-2011-4815 (a more detailed situation about the 
issue
is to follow this mail).  So everyone who uses 1.8.7 should consider
upgrading.

For details, please read the ChangeLog as usual.

ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.tar.gz
ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.tar.bz2
ftp://ftp.ruby-lang.org/pub/ruby/1.8/ruby-1.8.7-p357.zip

Checksums:

MD5(ruby-1.8.7-p357.tar.gz)= b2b8248ff5097cfd629f5b9768d1df82
SHA256(ruby-1.8.7-p357.tar.gz)=
2fdcac4eb37b2eba1a4eef392a2922e07a9222fc86d781d92154d716434b962c
SIZE(ruby-1.8.7-p357.tar.gz)= 4895136

MD5(ruby-1.8.7-p357.tar.bz2)= 3abd9e2a29f756a0d30c7bfca578cdeb
SHA256(ruby-1.8.7-p357.tar.bz2)=
5c64b63a597b4cb545887364e1fd1e0601a7aeb545e576e74a6d8e88a2765a37
SIZE(ruby-1.8.7-p357.tar.bz2)= 4208157

MD5(ruby-1.8.7-p357.zip)= 23efe7ba50458f8df691c7fa07ce0578
SHA256(ruby-1.8.7-p357.zip)=
b7672524ecac77e7f4bdbbfa5521109a0ef514d22bc726bad073d83b6044d445
SIZE(ruby-1.8.7-p357.zip)= 5994841


Have a happy new year,





 --
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-----Messaggio originale-----
Da: Urabe Shyouhei [mailto:shyouhei@ruby-lang.org]
Inviato: mercoled 28 dicembre 2011 14:33
A: ruby-talk ML; ruby-list@ruby-lang.org
Oggetto: [ANN] CVE-2011-4815: Denial of service attack was found for 
Ruby's
Hash algorithm

Subject:

Denial of service attack was found for Ruby's Hash algorithm

Impact:

This  is  something related  to  computational complexity.   Specially
crafted series of strings that intentionally collide their hash values
each other  was found.   With such sequences  an attacker can  issue a
denial  of  service attack  by,  for  instance,  giving them  as  POST
parameters of HTTP requests for your Rails application.

Detailed description:

The situation  is similar to the one  found for Perl in  2003.  In 1.8
series of Ruby, we use a deterministic hash function to hash a string.
Here the "deterministic"  means no other bits of  information than the 
input
string itself is involved to  generate a hash value.  So you can
precalculate a string's hash value beforehand.  By collecting a series 
of
strings  that have  the identical hash  value, an attacker  can let ruby
process collide  bins  of hash  tables  (including `Hash`  class
instances).   Hash   tables'  amortized  O(1)   attribute  depends  on
uniformity  of distribution of  hash values.   By giving  such crafted
input, an attacker can let  hash tables work much slower than expected
(namely O(n2) to construct a n-elements table this case).

Affected versions:

- Ruby 1.8.7-p352 and all prior versions.

All Ruby 1.9 series are not  affected by this kind of attack.  They do 
not
share hash implementations with Ruby 1.8 series.

Solution:

Our  solution  is  to  scramble  the  string  hash  function  by  some
PRNG-generated random bits.  By doing so a string's hashed value is no
longer deterministic.   That is, a `String#hash`  result is consistent
only for current process lifetime and will generate a different number 
for
the next boot.  To break  this situation an attacker must create a set 
of
strings which are robust  to this kind of  scrambling. This is believed 
to
be quite difficult.

Please upgrade to the latest version of ruby via my previous post.

http://mla.n-z.jp/?ruby-talk=391606

Notes:

* Bear  in  mind  that  the  solution _does_  _not_  _mean_  our  hash
  algorithm is  cryptographically secure.  To put it  simple, we fixed
  the  hash  table  but  we  didn't fix  `String#hash`  weakness.   An
  attacker could still exploit it once he / she got a pair of a string
  and its  hash value returned  from `String#hash`.  You  _must_ _not_
  disclose  `String#hash` outputs.   If you  need to  do  such things,
  consider using  secure hash algorithms instead.  Some  of them (such
  as SHA256) are provided in Ruby's standard library.

* For  those who  knows alternative  hash algorithms  inside  our code
  base: we  do not  support them (they  are disabled by  default).  By
  choosing them  we consider  you can read  C, and you  can understand
  what was wrong with the default  one.  Make sure that your choice is
  safe at your own risk.

Credit:

Credit  to  Alexander  Klink  <alexander.klink@nruns.com>  and  Julian
Waelde  <jwaelde@cdc.informatik.tu-darmstadt.de>  for  reporting  this
issue.




 --
 Caselle da 1GB, trasmetti allegati fino a 3GB e in piu' IMAP, POP3 e 
SMTP autenticato? GRATIS solo con Email.it http://www.email.it/f

 Sponsor:
 Riccione Hotel 3 stelle in centro: Pacchetto Capodanno mezza pensione, 
animazione bimbi, zona relax, parcheggio. Scopri l'offerta solo per 
oggi...
 Clicca qui: http://adv.email.it/cgi-bin/foclick.cgi?mid983&d)-12