Akshay Wattal wrote:
Lately i did some research on security issues related to
differnt package managers including YUM and found out that
there can be some vulnerabilities in YUM. So far YUM checks
the signature which is on each individual package,In this
model, the package manager has no signatures to check until
it gets to the point where it downloads the actual packages
it intends to install.
Keeping this in mind the vulnerabilities that are possible
are as follows:
---->Metadata Manipulation Attack: The attack in
this case involves a malicious party responding to a package
manager’s request by making their own metadata, There are
two main things attackers can do First, they can
mix-and-match the versions of packages that are listed.
Second, they can trick clients into thinking that packages
have different dependencies and provide different
functionality than they really do.
In mixing-and-matching vulnerable package versions by
listing them in the same metadata given to a client,
attackers make it more likely that, whatever new package a
client installs, it is installing a version with a known
I am not sure, but I think that Yum gets it dependencies from the
RPM headers, not the metadata. Also, the version number of a package
is in the RPM headers. It does not use the file name to determine
the version. So an older version of the package would not be
installed. If you mess with the headers to change the version
number, the signature would not match.
---->Freeze Attack: In this an attacker can keep giving
the client a single version of the metadata starting at one
point in time (that is, “freezing” the metadata), the
attacker can prevent the client from knowing about new
metadata and thus new packages that are available that fix
This only works if Yum uses the same mirror all the time. This is
not the case by default.
---->Endless data Attack: It involves a malicious party
responding to a client request, be it for metadata or for a
package, with an endless stream of data. The possible
effects include filling up the partition where the package
manager saves downloaded files or exhausting memory.
These are few "possible" vulnerabilities which can be found
Well, for any of these to work, the attacker has to first get on the
mirror list, or crack an existing mirror. Getting on the mirror list
would probably be easier..
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!