ArchLinux: 201708-13: strongswan: denial of service
Summary
Fixed a DoS vulnerability in the gmp plugin that was caused by insufficient input validation when verifying RSA signatures, which requires decryption with the operation m^e mod n, where m is the signature, and e and n are the exponent and modulus of the public key. The value m is an integer between 0 and n-1, however, the gmp plugin did not verify this. So if m equals n the calculation results in 0, in which case mpz_export() returns NULL. This result wasn't handled properly causing a null-pointer dereference.
Resolution
Upgrade to 5.5.3-4.
# pacman -Syu "strongswan>=5.5.3-4"
The problem has been fixed upstream but no release is available yet.
References
https://wiki.strongswan.org/versions/66 https://www.strongswan.org/blog/2017/08/14/strongswan-vulnerability-(cve-2017-11185).html https://security.archlinux.org/CVE-2017-11185
Workaround
None.