Siemens SCALANCE OpenSSL Allocation of Resources Without Limits or Throttling (CVE-2023-2650)

medium Tenable OT Security Plugin ID 501878

Synopsis

The remote OT asset is affected by a vulnerability.

Description

Issue summary: Processing some specially crafted ASN.1 object identifiers or data containing them may be very slow. Impact summary:
Applications that use OBJ_obj2txt() directly, or use any of the OpenSSL subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message size limit may experience notable to very long delays when processing those messages, which may lead to a Denial of Service. An OBJECT IDENTIFIER is composed of a series of numbers - sub-identifiers
- most of which have no size limit. OBJ_obj2txt() may be used to translate an ASN.1 OBJECT IDENTIFIER given in DER encoding form (using the OpenSSL type ASN1_OBJECT) to its canonical numeric text form, which are the sub-identifiers of the OBJECT IDENTIFIER in decimal form, separated by periods. When one of the sub-identifiers in the OBJECT IDENTIFIER is very large (these are sizes that are seen as absurdly large, taking up tens or hundreds of KiBs), the translation to a decimal number in text may take a very long time. The time complexity is O(n^2) with 'n' being the size of the sub-identifiers in bytes (*). With OpenSSL 3.0, support to fetch cryptographic algorithms using names / identifiers in string form was introduced. This includes using OBJECT IDENTIFIERs in canonical numeric text form as identifiers for fetching algorithms. Such OBJECT IDENTIFIERs may be received through the ASN.1 structure AlgorithmIdentifier, which is commonly used in multiple protocols to specify what cryptographic algorithm should be used to sign or verify, encrypt or decrypt, or digest passed data. Applications that call OBJ_obj2txt() directly with untrusted data are affected, with any version of OpenSSL. If the use is for the mere purpose of display, the severity is considered low. In OpenSSL 3.0 and newer, this affects the subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS. It also impacts anything that processes X.509 certificates, including simple things like verifying its signature.
The impact on TLS is relatively low, because all versions of OpenSSL have a 100KiB limit on the peer's certificate chain. Additionally, this only impacts clients, or servers that have explicitly enabled client authentication. In OpenSSL 1.1.1 and 1.0.2, this only affects displaying diverse objects, such as X.509 certificates. This is assumed to not happen in such a way that it would cause a Denial of Service, so these versions are considered not affected by this issue in such a way that it would be cause for concern, and the severity is therefore considered low.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Refer to the vendor advisory.

Plugin Details

Severity: Medium

ID: 501878

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 1/11/2024

Updated: 1/15/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2023-2650

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:siemens:scalance_xb205-3_firmware:-, cpe:/o:siemens:scalance_xb205-3ld_firmware:-, cpe:/o:siemens:scalance_xb208_firmware:-, cpe:/o:siemens:scalance_xb213-3_firmware:-, cpe:/o:siemens:scalance_xb213-3ld_firmware:-, cpe:/o:siemens:scalance_xb216_firmware:-, cpe:/o:siemens:scalance_xc206-2_firmware:-, cpe:/o:siemens:scalance_xc206-2g_poe_firmware:-, cpe:/o:siemens:scalance_xc206-2g_poe_eec_firmware:-, cpe:/o:siemens:scalance_xc206-2sfp_firmware:-, cpe:/o:siemens:scalance_xc206-2sfp_eec_firmware:-, cpe:/o:siemens:scalance_xc206-2sfp_g_firmware:-, cpe:/o:siemens:scalance_xc206-2sfp_g_eec_firmware:-, cpe:/o:siemens:scalance_xc208_firmware:-, cpe:/o:siemens:scalance_xc208eec_firmware:-, cpe:/o:siemens:scalance_xc208g_firmware:-, cpe:/o:siemens:scalance_xc208g_eec_firmware:-, cpe:/o:siemens:scalance_xc208g_poe_firmware:-, cpe:/o:siemens:scalance_xc216_firmware:-, cpe:/o:siemens:scalance_xc224_firmware:-, cpe:/o:siemens:scalance_xc224_4c_g_firmware:-, cpe:/o:siemens:scalance_xc224_4c_g_eec_firmware:-, cpe:/o:siemens:scalance_xf204_dna_firmware:-, cpe:/o:siemens:scalance_xf204_2ba_firmware:-, cpe:/o:siemens:scalance_xf204_2ba_dna_firmware:-, cpe:/o:siemens:scalance_xp208_firmware:-, cpe:/o:siemens:scalance_xp208eec_firmware:-, cpe:/o:siemens:scalance_xp208poe_eec_firmware:-, cpe:/o:siemens:scalance_xp216_firmware:-, cpe:/o:siemens:scalance_xp216eec_firmware:-, cpe:/o:siemens:scalance_xp216poe_eec_firmware:-, cpe:/o:siemens:scalance_xr324wg_firmware:-, cpe:/o:siemens:scalance_xr326-2c_poe_wg_firmware:-, cpe:/o:siemens:scalance_xr328-4c_wg_firmware:-, cpe:/o:siemens:siplus_net_scalance_xc206-2_firmware:-, cpe:/o:siemens:siplus_net_scalance_xc206-2sfp_firmware:-, cpe:/o:siemens:scalance_xc216_3g_poe_firmware:-, cpe:/o:siemens:scalance_xc216_4c_firmware:-, cpe:/o:siemens:scalance_xc216_4c_g_firmware:-, cpe:/o:siemens:scalance_xc216_4c_g_eec_firmware:-, cpe:/o:siemens:scalance_xc216eec_firmware:-, cpe:/o:siemens:siplus_net_scalance_xc208_firmware:-, cpe:/o:siemens:siplus_net_scalance_xc216-4c_firmware:-

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 5/30/2023

Vulnerability Publication Date: 5/30/2023

Reference Information

CVE: CVE-2023-2650

CWE: 770

Detections

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