Linux Encrypted Loop Filesystem Replay Attack Vulnerability
BID:3775
Info
Linux Encrypted Loop Filesystem Replay Attack Vulnerability
| Bugtraq ID: | 3775 |
| Class: | Design Error |
| CVE: |
CVE-2002-0570 |
| Remote: | No |
| Local: | Yes |
| Published: | Jan 02 2002 12:00AM |
| Updated: | Jul 11 2009 09:56AM |
| Credit: | Reported by Jerome Etienne <[email protected]> on January 2, 2002. |
| Vulnerable: |
Linux kernel 2.4.17 Linux kernel 2.4.16 Linux kernel 2.4.15 Linux kernel 2.4.14 Linux kernel 2.4.13 Linux kernel 2.4.12 Linux kernel 2.4.11 Linux kernel 2.4.10 Linux kernel 2.4.9 Linux kernel 2.4.8 Linux kernel 2.4.7 Linux kernel 2.4.6 Linux kernel 2.4.5 Linux kernel 2.4.4 Linux kernel 2.4.3 Linux kernel 2.4.2 Linux kernel 2.4.1 Linux kernel 2.4 Linux kernel 2.2.20 Linux kernel 2.2.19 Linux kernel 2.2.18 Linux kernel 2.2.17 Linux kernel 2.2.16 Linux kernel 2.2.15 Linux kernel 2.2.14 Linux kernel 2.2.13 Linux kernel 2.2.12 Linux kernel 2.2.11 Linux kernel 2.2.10 Linux kernel 2.2.9 Linux kernel 2.2.8 Linux kernel 2.2.7 Linux kernel 2.2.6 Linux kernel 2.2.5 Linux kernel 2.2.4 Linux kernel 2.2.3 Linux kernel 2.2.2 Linux kernel 2.2.1 Linux kernel 2.2 |
| Not Vulnerable: | |
Discussion
Linux Encrypted Loop Filesystem Replay Attack Vulnerability
Linux includes support for encrypted filesystems through a loop device. While a variety of encryption algorithms are supported, the basic operation is based on a block cipher in cipher block chaining (CBC) mode. Encryption is done individually on different blocks of the filesystem, and the same key is used throughout. While the initialization vector is different for each block (and is in fact based on the block number), the self correcting property of CBC ciphers allows a form of a replay attack.
Encrypted data may be copied between various areas of the file system. With the exception of the boundary area between the original and inserted data, the resulting plaintext will be correct. An attacker with knowledge of the physical layout of the file system may take advantage of this to replace data on the file system. Examples would include areas known to contain plain text, or guesses as to the locations of inode data.
Write access to the encrypted file system is required for this attack. This will generally require local or physical access to the machine or media. In general, it should not be assumed that integrity of data is provided for by this encryption model.
Linux includes support for encrypted filesystems through a loop device. While a variety of encryption algorithms are supported, the basic operation is based on a block cipher in cipher block chaining (CBC) mode. Encryption is done individually on different blocks of the filesystem, and the same key is used throughout. While the initialization vector is different for each block (and is in fact based on the block number), the self correcting property of CBC ciphers allows a form of a replay attack.
Encrypted data may be copied between various areas of the file system. With the exception of the boundary area between the original and inserted data, the resulting plaintext will be correct. An attacker with knowledge of the physical layout of the file system may take advantage of this to replace data on the file system. Examples would include areas known to contain plain text, or guesses as to the locations of inode data.
Write access to the encrypted file system is required for this attack. This will generally require local or physical access to the machine or media. In general, it should not be assumed that integrity of data is provided for by this encryption model.
Exploit / POC
Linux Encrypted Loop Filesystem Replay Attack Vulnerability
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
Solution / Fix
Linux Encrypted Loop Filesystem Replay Attack Vulnerability
Solution:
Currently the SecurityFocus staff are not aware of any vendor-supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
Solution:
Currently the SecurityFocus staff are not aware of any vendor-supplied patches for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
References
Linux Encrypted Loop Filesystem Replay Attack Vulnerability
References:
References: