Management summary
Due to insufficient validation of device certificates during connections used for device management, Siemens SICAM TOOLBOX II was vulnerable to Adversary-in-the-Middle (AiTM) attacks. The vendor provides a patched version V07.11 or higher since July 2025.
Vendor description
"Siemens SICAM Toolbox II - Engineering software for SICAM RTUs. SICAM TOOLBOX II provides all functions for integrated and standard engineering throughout the entire plant, e.g.: Data collection, data modeling, configuration, and parameterization. Engineering of process information for the automation and central control-room systems. SICAM TOOLBOX II is an ideal tool for plants and systems of all sizes."
Business recommendation
The vendor provides a patched version V07.11 or higher since July 2025.
SEC Consult highly recommends to perform a thorough security review of the product conducted by security professionals to identify and resolve potential further security issues.
Vulnerability overview/description
1) Improper device certificate validation enables AiTM attacks (CVE-2024-31853, CVE-2024-31854)
The SICAM Toolbox II connects with supported devices via an HTTPS connection (TCP port 443, TLS1.2). The Toolbox II software uses a hard-coded client certificate issued by the same Siemens CA when connecting to a device. Each device uses a device-specific certificate issued by a Siemens CA ("SICAM1703-Access-V1") as a server certificate. The certificate is generated/signed during the production process. The common name is the device serial number.
Due to a vulnerability in the certificate validation during the TLS connection, an attacker can perform an adversary-in-the-middle-attack.
The Toolbox II software only checks if the certificate was issued by the trusted CA, but does not check if the certificate is actually issued to the target device (e.g. by checking the certificate common name against an expected value). It is even possible to use the hard-coded Toolbox II client certificate instead of an actual device-specific certificate.
This attack can be used to steal RTU connection passwords, process data or modify the device configuration.
Proof of concept
1) Improper device certificate validation enables AiTM attacks (CVE-2024-31853, CVE-2024-31854)
An attacker requires the private key of any certificate issued by the "SICAM1703-Access-V1" CA for successful exploitation.
The most simple way to exploit the vulnerability is to extract the certificate/private key pair from the Toolbox II software. The P12 container can be found in the satzp.exe executable (located in /EMII/BIN/). The P12 file is stored in obfuscated form and de-obfuscated at runtime when establishing new TLS connections. Furthermore the P12 container is protected by a passphrase which is stored in obfuscated form as well.
Unlike a regular device-specific certificate, the common name of this certificate is "ToolboxII" and the extended key usage is "TLS Web Client Authentication".
Alternatively an attacker could also extract a device-specific certificate private key from a device (from the VaultIC chip).
Below is the Toolbox II client certificate and the corresponding private key (redacted).
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 2 (0x2)
Signature Algorithm: sha256WithRSAEncryption
Issuer: C = DE, ST = Deutschland, L = Berlin, O = Siemens AG, OU = Energy Automation, CN = SICAM1703-Access-V1
Validity
Not Before: Jan 1 01:01:01 2011 GMT
Not After : Dec 31 23:59:59 9999 GMT
Subject: C = DE, ST = Deutschland, L = Berlin, O = Siemens AG, OU = Energy Automation, CN = ToolboxII
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
RSA Public-Key: (2048 bit)
Modulus:
00:eb:56:a3:40:86:72:42:42:ca:1c:6c:25:41:11:
09:1d:20:ad:79:71:14:94:5c:02:a0:95:a6:ce:26:
1f:30:e2:21:9e:39:30:66:35:0c:df:77:e5:60:0b:
76:89:66:4a:08:f1:27:65:84:fc:d9:f1:b0:a3:b4:
4b:cf:dc:30:da:93:2b:74:e8:ac:3e:c5:5b:00:dd:
a9:03:79:f6:38:c5:1a:26:87:51:dd:1c:ad:72:b6:
c2:97:4c:62:f1:82:aa:86:e7:79:c9:82:b9:53:5b:
8d:40:26:76:1d:b0:03:2f:ce:ec:6e:f2:4a:af:79:
f3:e1:67:8b:c0:52:3b:f1:3e:dc:0d:8f:a4:f8:20:
e5:92:e3:ff:97:2b:34:a8:90:2c:79:42:3a:d0:e8:
ff:0d:d0:98:64:a8:5f:76:5f:e3:d8:bd:3e:85:3d:
49:33:ab:ae:54:5c:2a:2d:70:d0:95:3f:aa:cb:2d:
bf:34:f3:a2:f9:ae:17:a9:97:8f:a3:e2:ad:ad:f2:
ab:55:57:5b:04:56:b8:26:c3:fc:04:81:c9:ea:f5:
83:34:25:4a:22:9e:d5:73:6e:a4:d4:96:5b:65:3f:
cc:9d:97:df:6e:62:49:ae:a4:f2:4a:28:04:65:7d:
3d:7a:af:ba:69:49:75:32:a0:51:f0:93:69:fd:da:
eb:d1
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Subject Alternative Name:
email:support.energy@siemens.com
X509v3 Key Usage: critical
Digital Signature, Key Encipherment, Data Encipherment
X509v3 Extended Key Usage: critical
TLS Web Client Authentication
Signature Algorithm: sha256WithRSAEncryption
21:15:68:6e:5c:34:80:a7:95:d5:a9:fa:62:64:6f:16:63:c5:
8f:d6:42:c3:d3:dc:41:b4:98:e1:9c:13:47:d0:c7:c6:6c:66:
a5:27:1e:b2:f1:99:5b:17:cc:63:78:2e:d5:26:84:8a:58:68:
81:ee:f9:4f:0a:46:09:ec:23:77:e2:d6:f9:51:31:80:34:c3:
9f:e5:45:01:e4:e9:5e:2e:94:08:ea:80:7b:1b:25:01:95:32:
5c:6b:5b:30:8c:a5:5c:e4:b2:99:2a:83:22:ee:82:55:6e:d6:
38:57:8e:37:54:53:89:03:8d:1a:26:2c:15:a2:d9:6f:88:c5:
b0:a4:4b:e8:85:43:9d:25:c1:f4:eb:c0:b0:14:d0:7f:32:d7:
d1:54:34:28:7d:a7:59:ff:35:25:9f:33:df:18:8f:1f:74:cd:
c2:51:a0:06:35:d2:4d:c5:c3:b2:3e:b4:b0:05:fb:30:d1:c1:
44:44:84:d6:90:ce:24:b3:2f:a4:4a:8b:d0:04:11:50:22:16:
8e:39:1f:53:1d:e2:73:e0:c7:7b:2a:3a:4d:6b:83:e8:38:33:
a9:10:e8:f0:1d:42:d2:54:67:3b:14:7a:03:48:16:a3:cd:7b:
96:20:7f:de:cf:fc:ee:c6:37:e1:29:10:61:4f:22:de:46:cf:
d1:0d:8f:5a
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
-----BEGIN PRIVATE KEY-----
MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQDrVqNAhnJCQsoc
bCVBEQkdIK15cRSUXAKglabOJh8w4iGeOTBmNQzfd+VgC3aJZkoI8SdlhPzZ8bCj
tEvP3DDakyt06Kw+xVsA3akDefY4xRomh1HdHK1ytsKXTGLxgqqG53nJgrlTW41A
[...]
L7bTzPviSAvMQwaa5i6vJXCvhfB6q05rYgs4i/1eWQKBgQCkSGpuCF/ZwhQZ3KmD
rM7CoHgy4j2rbItWkIYbq9J5mJh7wpdYknY2pdRAocSLERiiLErFKU+k4QKilts2
oXLGKMem7ZxxvNVhij1g6Ypqm2bKWWkUsbW5X3WwGmYsGzMzeg+BhhxNn39Gq3QO
PkcoHTu5hSDvo1Y+qNakl2+3Hg==
-----END PRIVATE KEY-----Vulnerable / tested versions
The following version has been tested which was the latest version available at the time of the test:
- 7.1.0.0
According to the vendor, all versions before V07.11 are affected.