Siemens RUGGEDCOM, SCALANCE and SIMATIC Out-of-bounds Read (CVE-2021-3712)

high Tenable OT Security Plugin ID 505333

Synopsis

The remote OT asset is affected by a vulnerability.

Description

ASN.1 strings are represented internally within OpenSSL as an ASN1_STRING structure which contains a buffer holding the string data and a field holding the buffer length. This contrasts with normal C strings which are repesented as a buffer for the string data which is terminated with a NUL (0) byte. Although not a strict requirement, ASN.1 strings that are parsed using OpenSSL's own d2i functions (and other similar parsing functions) as well as any string whose value has been set with the ASN1_STRING_set() function will additionally NUL terminate the byte array in the ASN1_STRING structure. However, it is possible for applications to directly construct valid ASN1_STRING structures which do not NUL terminate the byte array by directly setting the data and length fields in the ASN1_STRING array. This can also happen by using the ASN1_STRING_set0() function. Numerous OpenSSL functions that print ASN.1 data have been found to assume that the ASN1_STRING byte array will be NUL terminated, even though this is not guaranteed for strings that have been directly constructed. Where an application requests an ASN.1 structure to be printed, and where that ASN.1 structure contains ASN1_STRINGs that have been directly constructed by the application without NUL terminating the data field, then a read buffer overrun can occur. The same thing can also occur during name constraints processing of certificates (for example if a certificate has been directly constructed by the application instead of loading it via the OpenSSL parsing functions, and the certificate contains non NUL terminated ASN1_STRING structures). It can also occur in the X509_get1_email(), X509_REQ_get1_email() and X509_get1_ocsp() functions. If a malicious actor can cause an application to directly construct an ASN1_STRING and then process it through one of the affected OpenSSL functions then this issue could be hit. This might result in a crash (causing a Denial of Service attack). It could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext). Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y).

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: High

ID: 505333

File Name: tenable_ot_siemens_CVE-2021-3712.nasl

Version: 1.2

Type: Remote

Family: Tenable.ot

Published: 4/22/2026

Updated: 4/23/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: High

Score: 7.7

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.3

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

CVSS Score Source: CVE-2021-3712

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.4

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

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

Vulnerability Information

CPE: cpe:/o:siemens:scalance_xr324-12m_%28230v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_x200-4p_irt_firmware:5.5.2, cpe:/o:siemens:siplus_s7-1200_cp_1243-1_rail_firmware:3.0.22, cpe:/o:siemens:scalance_x212-2ld_firmware:5.2.6, cpe:/o:siemens:scalance_x307-2_eec_%28230v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:scalance_x307-2_eec_%282x_24v%29_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rm1224_lte%284g%29_eu_firmware:7.1, cpe:/o:siemens:scalance_x206-1ld_firmware:5.2.6, cpe:/o:siemens:siplus_net_scalance_x308-2_firmware:4.5.2, cpe:/o:siemens:scalance_xr324-4m_poe_%28230v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_x308-2m_poe_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rox_mx5000re_firmware, cpe:/o:siemens:scalance_x306-1ld_fe_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-4m_eec_%2824v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:simatic_cp_1243-7_lte_us_firmware:3.3.46, cpe:/o:siemens:scalance_x302-7_eec_%28230v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:scalance_x224_firmware:5.2.6, cpe:/o:siemens:ruggedcom_rox_rx1400_firmware, cpe:/o:siemens:scalance_sc642-2c_firmware:2.3, cpe:/o:siemens:scalance_w786-2_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w1788-1_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w778-1_m12_eec_%28usa%29_firmware:6.6.0, cpe:/o:siemens:ruggedcom_rox_rx1500_firmware, cpe:/o:siemens:scalance_xr324-4m_poe_%2824v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-12m_%28230v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_m874-2_firmware:7.1, cpe:/o:siemens:scalance_x302-7_eec_%282x_24v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:scalance_x202-2p_irt_pro_firmware:5.5.2, cpe:/o:siemens:scalance_x307-2_eec_%2824v%29_firmware:4.1.4, cpe:/o:siemens:scalance_x302-7_eec_%282x_24v%29_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rm1224_lte%284g%29_nam_firmware:7.1, cpe:/o:siemens:scalance_x320-1-2ld_fe_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-4m_eec_%2824v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:siplus_s7-1200_cp_1243-1_firmware:3.3.46, cpe:/o:siemens:scalance_w761-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w788-2_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_xr324-4m_eec_%28100-240vac%2f60-250vdc%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:simatic_cp_1542sp-1_firmware:2.2.28, cpe:/o:siemens:scalance_x302-7_eec_%282x_230v%29_firmware:4.1.4, cpe:/o:siemens:scalance_wam766-1_firmware:1.2.0, cpe:/o:siemens:scalance_xr324-4m_poe_ts_%2824v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_w788-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_xf206-1_firmware:5.2.6, cpe:/o:siemens:scalance_x307-2_eec_%282x_230v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:siplus_et_200sp_cp_1543sp-1_isec_firmware:2.2.28, cpe:/o:siemens:scalance_x308-2m_ts_firmware:4.1.4, cpe:/o:siemens:scalance_x206-1_firmware:5.2.6, cpe:/o:siemens:ruggedcom_rox_rx1524_firmware, cpe:/o:siemens:scalance_sc636-2c_firmware:2.3, cpe:/o:siemens:scalance_s615_lan-router_firmware:2.3, cpe:/o:siemens:scalance_xf202-2p_irt_firmware:5.5.2, cpe:/o:siemens:scalance_x204-2ld_firmware:5.2.6, cpe:/o:siemens:scalance_x308-2_firmware:4.1.4, cpe:/o:siemens:scalance_xf201-3p_irt_firmware:5.5.2, cpe:/o:siemens:scalance_w786-2ia_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w778-1_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_w748-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w774-1_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_x307-3ld_firmware:4.1.4, cpe:/o:siemens:scalance_x302-7_eec_%28230v%29_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-4m_eec_%28100-240vac%2f60-250vdc%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_wum766-1_%28usa%29_firmware:5.2.6, cpe:/o:siemens:scalance_x308-2m_firmware:4.1.4, cpe:/o:siemens:scalance_m876-4_%28nam%29_firmware:7.1, cpe:/o:siemens:scalance_wum766-1_firmware:1.2.0, cpe:/o:siemens:simatic_cp_1243-8_irc_firmware:3.3.46, cpe:/o:siemens:scalance_x307-2_eec_%282x_230v%29_firmware:4.1.4, cpe:/o:siemens:scalance_m874-3_firmware:7.1, cpe:/o:siemens:scalance_w788-2_m12_firmware:6.6.0, cpe:/o:siemens:scalance_x202-2p_irt_firmware:5.5.2, cpe:/o:siemens:scalance_x302-7_eec_%2824v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:simatic_s7-1200_cpu_firmware:4.5.2, cpe:/o:siemens:scalance_mum853-1_%28eu%29_firmware:7.1, cpe:/o:siemens:scalance_mum856-1_%28eu%29_firmware:7.1, cpe:/o:siemens:scalance_x216_firmware:5.2.6, cpe:/o:siemens:scalance_sc646-2c_firmware:1.2.0, cpe:/o:siemens:scalance_m804pb_firmware:7.1, cpe:/o:siemens:scalance_xr324-12m_%2824v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_x201-3p_irt_pro_firmware:5.5.2, cpe:/o:siemens:scalance_w721-1_rj45_firmware:6.6.0, cpe:/o:siemens:siplus_net_cp_1543-1_firmware:1.1, cpe:/o:siemens:scalance_xf204-2_firmware:5.2.6, cpe:/o:siemens:scalance_x310fe_firmware:4.1.4, cpe:/o:siemens:scalance_m876-4_%28eu%29_firmware:7.1, cpe:/o:siemens:scalance_x310_firmware:4.1.4, cpe:/o:siemens:scalance_x320-1_fe_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rox_rx1536_firmware, cpe:/o:siemens:scalance_w1748-1_m12_firmware:3.0.0, cpe:/o:siemens:scalance_xr324-4m_poe_%2824v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_x208_firmware:5.2.6, cpe:/o:siemens:scalance_x204irt_pro_firmware:5.5.2, cpe:/o:siemens:scalance_x308-2lh%2b_firmware:4.1.4, cpe:/o:siemens:scalance_m816-1_adsl-router_firmware:7.1, cpe:/o:siemens:scalance_xr324-4m_eec_%282x_100-240vac%2f60-250vdc%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-12m_%2824v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_x202-2irt_firmware:5.5.2, cpe:/o:siemens:scalance_sc632-2c_firmware:2.3, cpe:/o:siemens:scalance_w788-2_rj45_firmware:7.1, cpe:/o:siemens:scalance_x204-2ld_ts_firmware:5.2.6, cpe:/o:siemens:scalance_x302-7_eec_%282x_230v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rox_rx1511_firmware, cpe:/o:siemens:scalance_xr324-12m_ts_%2824v%29_firmware:4.1.4, cpe:/o:siemens:ruggedcom_rox_mx5000_firmware, cpe:/o:siemens:simatic_cp_1242-7_v2_firmware:3.3.46, cpe:/o:siemens:scalance_mum856-1_%28row%29_firmware:1.1.1, cpe:/o:siemens:scalance_w774-1_rj45_%28usa%29_firmware:6.6.0, cpe:/o:siemens:scalance_x307-2_eec_%2824v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:scalance_w722-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_x308-2ld_firmware:4.1.4, cpe:/o:siemens:scalance_x308-2lh_firmware:4.1.4, cpe:/o:siemens:simatic_cp_1545-1_firmware:2020, cpe:/o:siemens:scalance_x408-2_firmware:4.1.4, cpe:/o:siemens:scalance_sc622-2c_firmware:2.3, cpe:/o:siemens:scalance_xr324-4m_eec_%282x_24v%2c_ports_on_rear%29_firmware:4.1.4, cpe:/o:siemens:scalance_xr324-4m_poe_%28230v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_w734-1_rj45_firmware:6.6.0, cpe:/o:siemens:ruggedcom_rox_rx1501_firmware, cpe:/o:siemens:simatic_cp_1543-1_firmware:3.0.22, cpe:/o:siemens:scalance_w778-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_w1788-2_m12_firmware:3.0.0, cpe:/o:siemens:scalance_m876-3_%28rok%29_firmware:7.1, cpe:/o:siemens:scalance_x208pro_firmware:5.2.6, cpe:/o:siemens:siplus_et_200sp_cp_1543sp-1_isec_tx_rail_firmware:3.0.0, cpe:/o:siemens:scalance_w738-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_x201-3p_irt_firmware:5.5.2, cpe:/o:siemens:simatic_cp_1543sp-1_firmware:2.2.28, cpe:/o:siemens:ruggedcom_rox_rx5000_firmware, cpe:/o:siemens:scalance_xr324-4m_eec_%282x_100-240vac%2f60-250vdc%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_m826-2_shdsl-router_firmware:7.1, cpe:/o:siemens:scalance_w734-1_rj45_%28usa%29_firmware:6.6.0, cpe:/o:siemens:scalance_x204-2_firmware:5.2.6, cpe:/o:siemens:scalance_x204-2fm_firmware:5.2.6, cpe:/o:siemens:scalance_xr324-4m_eec_%282x_24v%2c_ports_on_front%29_firmware:4.1.4, cpe:/o:siemens:scalance_w1788-2ia_m12_firmware:3.1, cpe:/o:siemens:ruggedcom_rox_rx1510_firmware, cpe:/o:siemens:scalance_wam766-1_eec_firmware:1.2.0, cpe:/o:siemens:scalance_x307-2_eec_%282x_24v%2c_coated%29_firmware:4.1.4, cpe:/o:siemens:scalance_w774-1_rj45_firmware:6.6.0, cpe:/o:siemens:siplus_s7-1200_cpu_firmware:5.5.2, cpe:/o:siemens:ruggedcom_rox_rx1512_firmware, cpe:/o:siemens:scalance_x212-2_firmware:5.2.6, cpe:/o:siemens:siplus_s7-1200_cpu_firmware:4.5.2, cpe:/o:siemens:scalance_w1788-2_eec_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w786-2_sfp_firmware:6.6.0, cpe:/o:siemens:scalance_w786-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_m876-3_firmware:7.1, cpe:/o:siemens:scalance_x302-7_eec_%2824v%29_firmware:4.1.4, cpe:/o:siemens:simatic_cp_1243-1_firmware:3.3.46, cpe:/o:siemens:simatic_cp_1243-7_lte_eu_firmware:3.3.46, cpe:/o:siemens:scalance_x307-3_firmware:4.1.4, cpe:/o:siemens:scalance_wam766-1_%28us%29_firmware:1.2.0, cpe:/o:siemens:scalance_x204-2ts_firmware:5.2.6, cpe:/o:siemens:scalance_xf204irt_firmware:6.6.0, cpe:/o:siemens:scalance_w788-1_m12_firmware:6.6.0, cpe:/o:siemens:siplus_net_cp_1242-7_v2_firmware:3.3.46, cpe:/o:siemens:scalance_w748-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_x204irt_firmware:5.5.2, cpe:/o:siemens:scalance_m812-1_adsl-router_firmware:7.1, cpe:/o:siemens:scalance_x304-2fe_firmware:4.1.4, cpe:/o:siemens:scalance_x307-2_eec_%28230v%29_firmware:4.1.4, cpe:/o:siemens:scalance_xf208_firmware:3.3.46, cpe:/o:siemens:scalance_wam766-1_eec_%28us%29_firmware:1.2.0, cpe:/o:siemens:scalance_xf204-2ba_irt_firmware:5.5.2, cpe:/o:siemens:scalance_xf204_firmware:5.2.6

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 2/8/2022

Vulnerability Publication Date: 8/24/2021

Reference Information

CVE: CVE-2021-3712

CWE: 125

ICSA: 22-069-09

Detections

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