Debian: Security Advisory for strongswan (DSA-4989-1)

The remote host is missing an update for the 'strongswan' package(s) announced via the DSA-4989-1 advisory.

Researchers at the United States of America National Security Agency (NSA) identified two denial of services vulnerability in strongSwan, an IKE/IPsec suite. CVE-2021-41990 RSASSA-PSS signatures whose parameters define a very high salt length can trigger an integer overflow that can lead to a segmentation fault. Generating a signature that bypasses the padding check to trigger the crash requires access to the private key that signed the certificate. However, the certificate does not have to be trusted. Because the gmp and the openssl plugins both check if a parsed certificate is self-signed (and the signature is valid), this can e.g. be triggered by an unrelated self-signed CA certificate sent by an initiator. CVE-2021-41991 Once the in-memory certificate cache is full it tries to randomly replace lesser used entries. Depending on the generated random value, this could lead to an integer overflow that results in a double-dereference and a call using out-of-bounds memory that most likely leads to a segmentation fault. Remote code execution can't be ruled out completely, but attackers have no control over the dereferenced memory, so it seems unlikely at this point.

'strongswan' package(s) on Debian Linux.

Checks if a vulnerable package version is present on the target host.

For the oldstable distribution (buster), these problems have been fixed in version 5.7.2-1+deb10u1. For the stable distribution (bullseye), these problems have been fixed in version 5.9.1-1+deb11u1. We recommend that you upgrade your strongswan packages.