CVE-2022-25218

Description

The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd_startup, allows an unauthenticated attacker on the local area network to achieve a significant degree of control over the "plaintext" to which an arbitrary blob of ciphertext will be decrypted by OpenSSL's RSA_public_decrypt() function. This weakness allows the attacker to manipulate the various iterations of the telnetd startup state machine and eventually obtain a root shell on the device, by means of an exchange of crafted UDP packets. In all versions but K2 22.5.9.163 and K3C 32.1.15.93 a successful attack also requires the exploitation of a null-byte interaction error (CVE-2022-25219).

References

ExploitThird Party Advisory

CvssV3 impact

BaseSeverity

HIGH

ConfidentialityImpact

HIGH

AttackComplexity

HIGH

Scope

UNCHANGED

AttackVector

NETWORK

AvailabilityImpact

HIGH

IntegrityImpact

HIGH

PrivilegesRequired

NONE

BaseScore

8.1

VectorString

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Version

3.1

UserInteraction

NONE

CvssV2 impact

AccessComplexity

MEDIUM

ConfidentialityImpact

COMPLETE

AvailabilityImpact

COMPLETE

IntegrityImpact

COMPLETE

BaseScore

9.3

VectorString

AV:N/AC:M/Au:N/C:C/I:C/A:C

Version

2.0

AccessVector

NETWORK

Authentication

NONE