CVE-2017-15643 in Anti Virus
Summary
by MITRE
An active network attacker (MiTM) can achieve remote code execution on a machine that runs IKARUS Anti Virus 2.16.7. IKARUS AV for Windows uses cleartext HTTP for updates along with a CRC32 checksum and an update value for verification of the downloaded files. The attacker first forces the client to initiate an update transaction by modifying an update field within an HTTP 200 response, so that it refers to a nonexistent update. The attacker then modifies the HTTP 404 response so that it specifies a successfully found update, with a Trojan horse executable file (e.g., guardxup.exe) and the correct CRC32 checksum for that file.
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Analysis
by VulDB Data Team • 11/27/2019
The vulnerability identified as CVE-2017-15643 represents a critical security flaw in IKARUS Anti Virus version 2.16.7 that enables remote code execution through a sophisticated man-in-the-middle attack vector. This vulnerability exploits the software's reliance on insecure communication protocols and weak validation mechanisms during the update process. The attack leverages the fact that IKARUS AV for Windows employs cleartext HTTP connections for software updates, which creates an ideal environment for network-based exploitation. The security implications are particularly severe because the vulnerability allows an attacker to execute arbitrary code on target systems without requiring any user interaction or authentication.
The technical implementation of this vulnerability stems from the software's update verification process that utilizes only CRC32 checksums and update value validation without cryptographic signatures or secure transport mechanisms. When a client attempts to download updates, the system first sends a request to a server that responds with an HTTP 200 status code containing a reference to a nonexistent update file. This initial response tricks the client into proceeding with the update process. Subsequently, the attacker intercepts the subsequent HTTP 404 response and modifies it to appear as a successful update with a malicious payload. The attacker specifically targets the guardxup.exe file as the Trojan horse executable, ensuring that the malicious file contains the correct CRC32 checksum to pass the validation check. This technique demonstrates a fundamental flaw in the update mechanism's trust model and validation procedures.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential lateral movement within network environments. An attacker who successfully exploits this vulnerability can install malware, modify system files, or establish persistent backdoors on infected systems. The attack requires only network access to intercept and modify HTTP traffic, making it particularly dangerous in environments where network traffic is not properly secured or monitored. The vulnerability affects all systems running IKARUS Anti Virus 2.16.7 that attempt to download updates from potentially compromised network connections, including corporate networks, public Wi-Fi, or any environment where man-in-the-middle attacks are possible.
The attack vector aligns with several common security frameworks and threat models, including the MITRE ATT&CK framework's techniques for execution through remote services and command and control communications. This vulnerability specifically relates to CWE-319 (Cleartext Transmission of Sensitive Information) and CWE-345 (Insufficient Verification of Data Authenticity) categories, highlighting the fundamental security weaknesses in the implementation. Organizations affected by this vulnerability should immediately implement network segmentation to prevent unauthorized access to update servers, deploy secure update mechanisms using HTTPS with certificate validation, and consider implementing network monitoring to detect and prevent malicious update traffic. The recommended mitigation strategy includes upgrading to a patched version of IKARUS Anti Virus, implementing proper network security controls, and ensuring that all update communications occur over encrypted channels. Additionally, system administrators should conduct thorough vulnerability assessments to identify any other software components that might be using similar insecure update mechanisms.