Security Vulnerabilities - CVEs Published In September 2023
In EVE OS, the “measured boot” mechanism prevents a compromised device from accessing
the encrypted data located in the vault.
As per the “measured boot” design, the PCR values calculated at different stages of the boot
process will change if any of their respective parts are changed.
This includes, among other things, the configuration of the bios, grub, the kernel cmdline,
initrd, and more.
However, this mechanism does not validate the entire rootfs, so an attacker can edit the
filesystem and gain control over the system.
As the default filesystem used by EVE OS is squashfs, this is somewhat harder than an ext4,
which is easily changeable.
This will not stop an attacker, as an attacker can repackage the squashfs with their changes
in it and replace the partition altogether.
This can also be done directly on the device, as the “003-storage-init” container contains the
“mksquashfs” and “unsquashfs” binaries (with the corresponding libs).
An attacker can gain full control over the device without changing the PCR values, thus not
triggering the “measured boot” mechanism, and having full access to the vault.
Note:
This issue was partially fixed in these commits (after disclosure to Zededa), where the config
partition measurement was added to PCR13:
• aa3501d6c57206ced222c33aea15a9169d629141
• 5fef4d92e75838cc78010edaed5247dfbdae1889.
This issue was made viable in version 9.0.0 when the calculation was moved to PCR14 but it was not included in the measured boot.
CVSS Score
8.8
EPSS Score
0.0
Published
2023-09-20
A flaw was found in the offline_access scope in Keycloak. This issue would affect users of shared computers more (especially if cookies are not cleared), due to a lack of root session validation, and the reuse of session ids across root and user authentication sessions. This enables an attacker to resolve a user session attached to a previously authenticated user; when utilizing the refresh token, they will be issued a token for the original user.
CVSS Score
6.8
EPSS Score
0.002
Published
2023-09-20
A Type Confusion vulnerability was found in the Spotlight RPC functions in afpd in Netatalk 3.1.x before 3.1.17. When parsing Spotlight RPC packets, one encoded data structure is a key-value style dictionary where the keys are character strings, and the values can be any of the supported types in the underlying protocol. Due to a lack of type checking in callers of the dalloc_value_for_key() function, which returns the object associated with a key, a malicious actor may be able to fully control the value of the pointer and theoretically achieve Remote Code Execution on the host. This issue is similar to CVE-2023-34967.
CVSS Score
9.8
EPSS Score
0.066
Published
2023-09-20
PCR14 is not in the list of PCRs that seal/unseal the “vault” key, but
due to the change that was implemented in commit
“7638364bc0acf8b5c481b5ce5fea11ad44ad7fd4”, fixing this issue alone would not solve the
problem of the config partition not being measured correctly.
Also, the “vault” key is sealed/unsealed with SHA1 PCRs instead of
SHA256.
This issue was somewhat mitigated due to all of the PCR extend functions
updating both the values of SHA256 and SHA1 for a given PCR ID.
However, due to the change that was implemented in commit
“7638364bc0acf8b5c481b5ce5fea11ad44ad7fd4”, this is no longer the case for PCR14, as
the code in “measurefs.go” explicitly updates only the SHA256 instance of PCR14, which
means that even if PCR14 were to be added to the list of PCRs sealing/unsealing the “vault”
key, changes to the config partition would still not be measured.
An attacker could modify the config partition without triggering the measured boot, this could
result in the attacker gaining full control over the device with full access to the contents of the
encrypted “vault”
CVSS Score
8.8
EPSS Score
0.0
Published
2023-09-20
Vault Key Sealed With SHA1 PCRs
The measured boot solution implemented in EVE OS leans on a PCR locking mechanism.
Different parts of the system update different PCR values in the TPM, resulting in a unique
value for each PCR entry.
These PCRs are then used in order to seal/unseal a key from the TPM which is used to
encrypt/decrypt the “vault” directory.
This “vault” directory is the most sensitive point in the system and as such, its content should
be protected.
This mechanism is noted in Zededa’s documentation as the “measured boot” mechanism,
designed to protect said “vault”.
The code that’s responsible for generating and fetching the key from the TPM assumes that
SHA256 PCRs are used in order to seal/unseal the key, and as such their presence is being
checked.
The issue here is that the key is not sealed using SHA256 PCRs, but using SHA1 PCRs.
This leads to several issues:
• Machines that have their SHA256 PCRs enabled but SHA1 PCRs disabled, as well
as not sealing their keys at all, meaning the “vault” is not protected from an attacker.
• SHA1 is considered insecure and reduces the complexity level required to unseal the
key in machines which have their SHA1 PCRs enabled.
An attacker can very easily retrieve the contents of the “vault”, which will effectively render
the “measured boot” mechanism meaningless.
CVSS Score
8.8
EPSS Score
0.0
Published
2023-09-20
fake_upload.cgi on the Telstra Smart Modem Gen 2 (Arcadyan LH1000), firmware versions < 0.18.15r, allows unauthenticated attackers to upload firmware images and configuration backups, which could allow them to alter the firmware or the configuration on the device, ultimately leading to code execution as root.
CVSS Score
8.8
EPSS Score
0.033
Published
2023-09-20
D-Link device DI-7200GV2.E1 v21.04.09E1 was discovered to contain a stack overflow via the id parameter in the yyxz.data function.
CVSS Score
9.8
EPSS Score
0.007
Published
2023-09-20
D-Link device DI-7200GV2.E1 v21.04.09E1 was discovered to contain a stack overflow via the hi_up parameter in the qos_ext.asp function.
CVSS Score
9.8
EPSS Score
0.019
Published
2023-09-20
D-LINK DWL-6610 FW_v_4.3.0.8B003C was discovered to contain a command injection vulnerability in the function pcap_download_handler. This vulnerability allows attackers to execute arbitrary commands via the update.device.packet-capture.tftp-file-name parameter.
CVSS Score
9.8
EPSS Score
0.015
Published
2023-09-20
D-LINK DWL-6610 FW_v_4.3.0.8B003C was discovered to contain a stack overflow vulnerability in the function update_users.
CVSS Score
9.8
EPSS Score
0.005
Published
2023-09-20