Sławomir Rozbicki

RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures during X.509 validation. Due to the inclusion of an e=3 root CA in its trust store, an attacker who controls or redirects an outbound TLS connection can utilize the root public certificate to forge a trusted intermediate certificate and issue certificates for arbitrary hostnames, allowing for TLS server impersonation.

WebFig contains an unauthenticated file-read issue in the '/jsproxy' endpoint. A newly allocated session retains a stale uninitialized principal pointer used for file authorization. An unauthenticated attacker can manipulate the allocator to cause the file-serving path to dereference this pointer with elevated rights. By supplying parent-directory components in an encrypted URI, the attacker can escape the WebFig file namespace and disclose root-owned files, such as configuration stores containing credentials.

An issue exists in the SSH protocol implementation where the system fails to compare the complete RSA public key when matching an authentication request to an authorized user key. Specifically, the system verifies the key type and modulus but omits the exponent. Since signature verification relies on the client-supplied key, an attacker who knows an authorized RSA modulus can provide a key with an exponent of one to forge a valid signature. This allows the attacker to bypass security restrictions and open an SSH command channel as the target user without possessing the private key, potentially granting full control over the device. This issue has been actively exploited in the wild.

An unauthenticated client can initiate an IPv4 UDP test by exploiting a state where the system accepts a related btest connection before the primary session authentication is complete. When the `random-data` variable is set to `false`, the sender transmits an uninitialized tail from a kernel packet buffer. Additionally, an unchecked, inverted packet-size interval leads to an unsigned integer underflow, resulting in anomalously large fragmented output and a potential restart of the RouterOS kernel.

An argument-handling flaw exists in the SSH login path. By using a username that begins with a prohibited character, an unauthenticated attacker can reach the RouterOS login helper and modify the trusted RouterOS policy mask. This improper neutralization of argument delimiters allows for privilege escalation, potentially granting administrative access without credentials.

The SSH server improperly enforces the behavioral workflow during a client-requested rekey. This allows an unauthenticated client to bypass authentication, open a session channel, and send an exec request. The server then dispatches the command, enabling the unauthenticated creation, overwrite, and reconstruction of files within the managed file namespace, including support files that contain configuration and diagnostic data.