The API function `ssh_get_hexa()` is vulnerable, when 0-lenght
input is provided to this function. This function is used internally
in `ssh_get_fingerprint_hash()` and `ssh_print_hexa()` (deprecated),
which is vulnerable to the same input (length is provided by the
calling application). The function is also used internally in the gssapi code for logging
the OIDs received by the server during GSSAPI authentication.
This
could be triggered remotely, when the server allows GSSAPI authentication
and logging verbosity is set at least to SSH_LOG_PACKET (3). This
could cause self-DoS of the per-connection daemon process.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
Low
Partial disruption
CVSS Vector v3.0