Critical Vulnerability in Dropbear: Filename Handling Flaw
Summary
ALPINE-CVE-2020-36254: scp.c in Dropbear before 2020.79 mishandles the filename of . or an empty filename, a related issue to CVE-2018-20685. Affects dropbear versions < 2019.78-r1. Fixed in 2019.78-r1. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
Dropbear is a lightweight SSH server and client designed for resource-limited environments. It is widely used in embedded systems and provides secure shell access to remote devices. The package is known for its efficiency and small footprint, making it a popular choice among developers. However, it has been found to have a vulnerability that affects its handling of filenames, particularly when dealing with '.' or empty filenames.
Vulnerability Detail
The vulnerability, identified as CVE-2020-36254, exists in the scp.c file of Dropbear versions prior to 2020.79. It mishandles the filename when the input is '.' or an empty string, which can lead to unintended file operations. This flaw can potentially allow an attacker to manipulate file transfers, leading to data exposure or corruption. The severity of this vulnerability is reflected in its CVSS score of 8.1, indicating a high risk to systems using affected versions of Dropbear.
How To Fix
Minimum fixed version
2019.78-r1
This is the first release that contains the fix.
sudo apk add --upgrade dropbearTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid using '.' or empty filenames in their SCP commands until the package is updated. This can help mitigate the risk of exploitation while waiting for a permanent fix.
Conclusion
The vulnerability CVE-2020-36254 in Dropbear poses a significant risk due to improper filename handling. Users are strongly advised to update to the patched version 2019.78-r1 or later to mitigate this risk. Until then, avoiding certain filename inputs can serve as a temporary measure.
See every vulnerability recorded for dropbear →
FAQ
CVE-2020-36254 is a vulnerability in Dropbear that affects how the software handles filenames, specifically '.' or empty strings, potentially leading to unauthorized file operations.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score of CVE-2020-36254 is 8.1, indicating a high severity level that requires immediate attention.
If an immediate update is not possible, avoid using '.' or empty filenames in your SCP commands as a temporary workaround.
More information about Dropbear can be found on its official website or through its documentation, which provides insights into its features and usage.
References
Related vulnerabilities
Recent vulnerabilities recorded for dropbear.
