CVE-2017-8415

CRITICALCVSS 9.8/10EPSS 3.93%

Last modified

CVE-2017-8415 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device has a custom telnet daemon as a part of the busybox and retrieves the password from the shadow file using the function getspnam at address 0x00053894. EPSS estimates a 3.93% chance of exploitation in the next 30 days.

Description

An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device has a custom telnet daemon as a part of the busybox and retrieves the password from the shadow file using the function getspnam at address 0x00053894. Then performs a crypt operation on the password retrieved from the user at address 0x000538E0 and performs a strcmp at address 0x00053908 to check if the password is correct or incorrect. However, the /etc/shadow file is a part of CRAM-FS filesystem which means that the user cannot change the password and hence a hardcoded hash in /etc/shadow is used to match the credentials provided by the user. This is a salted hash of the string "admin" and hence it acts as a password to the device which cannot be changed as the whole filesystem is read only.

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
3.93%

89.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
DlinkDcs-1130 FirmwareAll versions
DlinkDcs-1100 FirmwareAll versions

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2017-8415?
An issue was discovered on D-Link DCS-1100 and DCS-1130 devices. The device has a custom telnet daemon as a part of the busybox and retrieves the password from the shadow file using the function getspnam at address 0x00053894. Then performs a crypt operation on the password retrieved from the user at address 0x000538E0 and performs a strcmp at address 0x00053908 to check if the password is correct or incorrect. However, the /etc/shadow file is a part of CRAM-FS filesystem which means that the user cannot change the password and hence a hardcoded hash in /etc/shadow is used to match the credentials provided by the user. This is a salted hash of the string "admin" and hence it acts as a password to the device which cannot be changed as the whole filesystem is read only.
How severe is CVE-2017-8415?
CVE-2017-8415 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 3.93% probability of exploitation in the next 30 days.
How do I fix CVE-2017-8415?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2017-8415?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST