Integrity Validation Bypass in CryptoPro Secure Disk for BitLocker
The CPSD CryptoPro Secure Disk application boots a small Linux operating system to perform user authentication before using BitLocker to decrypt the Windows partition. The system is located on a separate unencrypted partition which can be reached by anyone with access to the hard disk.
Multiple checks are performed to validate the integrity of the Linux operating system and the CryptoPro Secure Disk application files. When files are changed an error is shown on system start. One of the checks is the Linux kernel's Integrity Measurement Architecture (IMA). It was identified that configuration files are not validated by the IMA and can then (if not checked by other measures) be changed. This allows an attacker to execute arbitrary code in the context of the root user and enables an attacker to e.g., plant a backdoor and access data during execution.
Integrity Validation Bypass in CryptoPro Secure Disk for BitLocker
The CPSD CryptoPro Secure Disk application boots a small Linux operating system to perform user authentication before using BitLocker to decrypt the Windows partition. The system is located on a separate unencrypted partition which can be reached by anyone with access to the hard disk.
Multiple checks are performed to validate the integrity of the Linux operating system and the CryptoPro Secure Disk application files. When files are changed an error is shown on system start. One of the checks is the Linux kernel's Integrity Measurement Architecture (IMA). It was identified that configuration files are not validated by the IMA and can then (if not checked by other measures) be changed. This allows an attacker to execute arbitrary code in the context of the root user and enables an attacker to e.g., plant a backdoor and access data during execution.
The vendor provides a patch with version 7.6.6 / 7.7.1. Encryption is activated by default starting with version 7.7.
Configurations
Workarounds
Encryption of the PBA partition is possible (since version 7.6.0) and prevents changing of the configuration files. Encryption can be activated via "Client Security/Verschiedenes/PBA Linux Partition verschlüsseln". Clients will be informed by the vendor about the risk if the PBA partition is not encrypted.
The CPSD CryptoPro Secure Disk application boots a small Linux operating system to perform user authentication before using BitLocker to decrypt the Windows partition. The system is located on a separate unencrypted partition which can be reached by anyone with access to the hard disk.
Multiple checks are performed to validate the integrity of the Linux operating system and the CryptoPro Secure Disk application files. When files are changed an error is shown on system start. One of the checks is the Linux kernel's Integrity Measurement Architecture (IMA). It was identified that configuration files are not validated by the IMA and can then (if not checked by other measures) be changed. This allows an attacker to execute arbitrary code in the context of the root user and enables an attacker to e.g., plant a backdoor and access data during execution.
Known To Be Used In Ransomware Campaigns?-Not Available
KEV Added-Not Available
KEV Action Due Date-Not Available
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