Strongswan vulnerabilities

libcharon in strongSwan 5.9.7 through 6.0.7 mishandles behavioral workflow in the IKEv2 state machine. Because CREATE_CHILD_SA requests are mishandled, there can be an authentication bypass.

strongSwan 4.5.0 through 6.0.7 has Incorrect Access Control in the eap-ttls and eap-peap plugins because there can be a missing or mismatched inner EAP identity.

libcharon in strongSwan 6.0.0 through 6.0.7 has a use-after-free in IKEv2 rekeying collision handling.

strongSwan 5.1.3 through 6.0.7 has an infinite loop in the x509 plugin's attribute certificate parser for ietfAttrSyntax.

strongSwan 4.2.0 through 6.0.7 has a NULL pointer dereference in the x509 plugin's attribute certificate parser.

In strongSwan before 6.0.7, identity parsing/cloning is mishandled. Parsed EAP-Identities that result in an empty but non-NULL encoding are not correctly cloned and trigger a double-free once the duplicates are destroyed.

strongSwan versions 4.5.0 prior to 6.0.5 contain an integer underflow vulnerability in the EAP-TTLS AVP parser that allows unauthenticated remote attackers to cause a denial of service by sending crafted AVP data with invalid length fields during IKEv2 authentication. Attackers can exploit the failure to validate AVP length fields before subtraction to trigger excessive memory allocation or NULL pointer dereference, crashing the charon IKE daemon.

strongMan is a management interface for strongSwan, an OpenSource IPsec-based VPN. When storing credentials in the database (private keys, EAP secrets), strongMan encrypts the corresponding database fields. So far it used AES in CTR mode with a global database key. Together with an initialization vector (IV), a key stream is generated to encrypt the data in the database fields. But because strongMan did not generate individual IVs, every database field was encrypted using the same key stream. An attacker that has access to the database can use this to recover the encrypted credentials. In particular, because certificates, which have to be considered public information, are also encrypted using the same mechanism, an attacker can directly recover a large chunk of the key stream, which allows them to decrypt basically all other secrets especially ECDSA private keys and EAP secrets, which are usually a lot shorter. Version 0.2.0 fixes the issue by switching to AES-GCM-SIV encryption with a random nonce and an individually derived encryption key, using HKDF, for each encrypted value. Database migrations are provided to automatically re-encrypt all credentials.

In the eap-mschapv2 plugin (client-side) in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 through 8, and cause an integer underflow that potentially results in a heap-based buffer overflow.