CVE-2020-7593 in LOGO! 8 BM
Summary
by MITRE
A vulnerability has been identified in LOGO! 8 BM (incl. SIPLUS variants) (V1.81.01 - V1.81.03), LOGO! 8 BM (incl. SIPLUS variants) (V1.82.01), LOGO! 8 BM (incl. SIPLUS variants) (V1.82.02). A buffer overflow vulnerability exists in the Web Server functionality of the device. A remote unauthenticated attacker could send a specially crafted HTTP request to cause a memory corruption, potentially resulting in remote code execution.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/15/2020
The vulnerability identified in LOGO! 8 BM devices represents a critical buffer overflow flaw within the web server component that affects multiple firmware versions including V1.81.01 through V1.81.03 and V1.82.01 through V1.82.02. This issue specifically targets the HTTP request handling mechanism where insufficient input validation allows attackers to manipulate memory structures through crafted requests. The vulnerability exists in the embedded web server functionality that enables remote access to the industrial automation device, making it particularly dangerous in operational technology environments where these devices are commonly deployed.
The technical nature of this flaw aligns with CWE-121, which describes buffer overflow conditions where insufficient boundary checking allows data to overwrite adjacent memory locations. The vulnerability manifests when the web server processes HTTP requests without proper validation of input length or content, enabling an attacker to supply data exceeding the allocated buffer space. This memory corruption can potentially be exploited to execute arbitrary code on the affected device, as the overflow may overwrite critical program execution pointers or return addresses. The remote unauthenticated nature of the attack means that adversaries can exploit this vulnerability without requiring prior access credentials or physical presence at the device location.
From an operational perspective, this vulnerability poses significant risks to industrial control systems and building automation environments where LOGO! 8 BM devices are commonly deployed. The potential for remote code execution could allow attackers to gain full control over the automation logic, potentially disrupting critical processes or enabling lateral movement within network segments. The impact extends beyond simple device compromise as these devices often control essential functions such as lighting, heating, ventilation, and air conditioning systems. The vulnerability's presence in SIPLUS variants indicates the risk affects both standard and enhanced industrial-grade deployments, making it particularly concerning for mission-critical infrastructure environments where reliability and security are paramount.
The attack surface for this vulnerability encompasses any network-accessible LOGO! 8 BM device running the affected firmware versions, with the risk being heightened by the lack of authentication requirements for exploitation. Security professionals should consider this vulnerability in relation to ATT&CK framework techniques such as T1210 - Exploitation of Remote Services and T1059 - Command and Scripting Interpreter, as the remote code execution capability enables adversaries to establish persistent access and potentially escalate privileges. Mitigation strategies should include immediate firmware updates from Siemens, network segmentation to isolate affected devices, and implementation of intrusion detection systems to monitor for suspicious HTTP traffic patterns. Organizations should also conduct comprehensive vulnerability assessments to identify all instances of affected devices within their operational technology environments and implement network access controls to prevent unauthorized remote access to these critical automation systems.