Since it's the signature (not a key), this is only vulnerable to
freeze/rewind attacks. i.e. Only matching file/signature pairs can be
replaced on the wire. It's not possible to replace the contents
arbitrarily.

** Description changed:

  Binary package hint: update-manager-core
  
  I think update-manager has a security problem:
  
  # grep URI /etc/update-manager/meta-release | head -2
  URI = http://changelogs.ubuntu.com/meta-release
  URI_LTS = http://changelogs.ubuntu.com/meta-release-lts
  
  Changelogs are checked over the url: http://changelogs.ubuntu.com/meta-
  release where you will find something like this:
  
  Dist: maverick
  [..]
  UpgradeTool: 
http://archive.ubuntu.com/ubuntu/dists/maverick-updates/main/dist-upgrader-all/current/maverick.tar.gz
  UpgradeToolSignature: 
http://archive.ubuntu.com/ubuntu/dists/maverick-updates/main/dist-upgrader-all/current/maverick.tar.gz.gpg
  
  Presumably, the UpgradeToolSignature is used to verify the UpgradeTool.
  
  So update-manager does two things:
- * Gets a key that verifies a file.
+ * Gets a signature that verifies a file.
  * Get a file.
- * Checks the key verifies the file.
+ * Checks the signature verifies the file.
  
- But because this is happening over http without ssl, the key or the file
- or both can be replaced.
+ But because this is happening over http without ssl, the signature or
+ the file or both can be replaced.

** Changed in: update-manager-core (Ubuntu)
   Importance: Undecided => Wishlist

** Changed in: update-manager-core (Ubuntu)
       Status: New => Confirmed

** Visibility changed to: Public

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https://bugs.launchpad.net/bugs/701378

Title:
  update-manager seems to insecurely check if a file is valid

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