Hello, On Thu, Aug 14, 2025 at 08:19:00AM -0700, Paul Eggert wrote: > On 8/14/25 05:28, Pavel Raiskup wrote: > > Can't this security measure be worked-around with concatenated archives > > (tar --append)? > > I don't see how. Can you give an example?
The security measure was "each one should be extracted independently, into different empty directories" and I am not sure whether Pavel meant "worked around by the attacker", i.e. delivering the attack even with a single archive. If so, I believe the answer is no - if I concatenate the two archives with --catenate or create a combined one with --append, the attack does not work. This shows that the attack might be worked around by the victim: if they do not want to extract into different emptyu directories, they could concatenate the archives, and then extract the combined one in a single command, and they should be safe. Regards, Pavel
