diff options
| author | Ori Bernstein <ori@eigenstate.org> | 2022-06-30 01:24:27 +0000 |
|---|---|---|
| committer | Ori Bernstein <ori@eigenstate.org> | 2022-06-30 01:24:27 +0000 |
| commit | e6d31c1715cc50bd3d9a0301a41647295f739071 (patch) | |
| tree | 883c42bf6670266cfad40bea4d21d8198cbd85ba /sys/src/cmd/nusb/ptp/ptp.c | |
| parent | 1f95e98dddc420321a8942d9f3195d966c7cc6c0 (diff) | |
spf: limit recursion depth to prevent ddos (thanks tijay, iashiq5)
An attacker may use an infinite number of SPF referrals in his/her SPF
setting and can send an email to your mail server which would make
your SMTP server make a lot of DNS queries. By exploiting this
vulnerability, an attacker can block your SMTP queue, flood the
associated recursive resolver, or any DNS authoritative server.
According to RFC recommendations
(https://datatracker.ietf.org/doc/html/rfc7208#section-4.6), a few DNS
lookup limits exist that an SMTP server needs to maintain while
resolving an SPF record. That is, SPF implementations MUST limit the
total number of query-causing terms to 10 and the number of void
lookups to 2 to avoid unreasonable load on the DNS.
from:
Taejoong “Tijay” Chung (tijay@vt.edu)
Ishtiaq Ashiq (iashiq5@vt.edu)
Diffstat (limited to 'sys/src/cmd/nusb/ptp/ptp.c')
0 files changed, 0 insertions, 0 deletions