Vulnerabilities

An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

scp.c in Dropbear before 2020.79 mishandles the filename of . or an empty filename, a related issue to CVE-2018-20685.

Dropbear 2011.54 through 2018.76 has an inconsistent failure delay that may lead to revealing valid usernames, a different issue than CVE-2018-15599.

It was found that dropbear before version 2013.59 with GSSAPI leaks whether given username is valid or invalid. When an invalid username is given, the GSSAPI authentication failure was incorrectly counted towards the maximum allowed number of password attempts.

The recv_msg_userauth_request function in svr-auth.c in Dropbear through 2018.76 is prone to a user enumeration vulnerability because username validity affects how fields in SSH_MSG_USERAUTH messages are handled, a similar issue to CVE-2018-15473 in an unrelated codebase.

The server in Dropbear before 2017.75 might allow post-authentication root remote code execution because of a double free in cleanup of TCP listeners when the -a option is enabled.

Format string vulnerability in Dropbear SSH before 2016.74 allows remote attackers to execute arbitrary code via format string specifiers in the (1) username or (2) host argument.

CRLF injection vulnerability in Dropbear SSH before 2016.72 allows remote authenticated users to bypass intended shell-command restrictions via crafted X11 forwarding data.