A vulnerability was found in lighttpd up to 1.4.49 (Web Server). It has been rated as critical. Affected by this issue is an unknown code block of the file mod_alias.c of the component mod_alias_physical_handler. The manipulation with the input value ../ leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality, integrity, and availability. CVE summarizes:

An issue was discovered in mod_alias_physical_handler in mod_alias.c in lighttpd before 1.4.50. There is potential ../ path traversal of a single directory above an alias target, with a specific mod_alias configuration where the matched alias lacks a trailing '/' character, but the alias target filesystem path does have a trailing '/' character.

The bug was discovered 07/02/2018. The weakness was published 11/07/2018 (Website). The advisory is available at github.com. This vulnerability is handled as CVE-2018-19052 since 11/06/2018. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

The vulnerability was handled as a non-public zero-day exploit for at least 42 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 119607 (lighttpd < 1.4.50 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Web Servers and running in the context r.

Upgrading to version 1.4.50 eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (119607). Similar entries are available at VDB-75566, VDB-75579, VDB-86018 and VDB-86019.

Productinfo

Type

• Web Server

Name

• lighttpd

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10
• 1.4.11
• 1.4.12
• 1.4.13
• 1.4.14
• 1.4.15
• 1.4.16
• 1.4.17
• 1.4.18
• 1.4.19
• 1.4.20
• 1.4.21
• 1.4.22
• 1.4.23
• 1.4.24
• 1.4.25
• 1.4.26
• 1.4.27
• 1.4.28
• 1.4.29
• 1.4.30
• 1.4.31
• 1.4.32
• 1.4.33
• 1.4.34
• 1.4.35
• 1.4.36
• 1.4.37
• 1.4.38
• 1.4.39
• 1.4.40
• 1.4.41
• 1.4.42
• 1.4.43
• 1.4.44
• 1.4.45
• 1.4.46
• 1.4.47
• 1.4.48
• 1.4.49

License

• open-source

CPE 2.3info

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CPE 2.2info

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