Vulnerabilities > CVE-2019-11072 - Integer Overflow or Wraparound vulnerability in Lighttpd
Summary
lighttpd before 1.4.54 has a signed integer overflow, which might allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a malicious HTTP GET request, as demonstrated by mishandling of /%2F? in burl_normalize_2F_to_slash_fix in burl.c. NOTE: The developer states "The feature which can be abused to cause the crash is a new feature in lighttpd 1.4.50, and is not enabled by default. It must be explicitly configured in the config file (e.g. lighttpd.conf). Certain input will trigger an abort() in lighttpd when that feature is enabled. lighttpd detects the underflow or realloc() will fail (in both 32-bit and 64-bit executables), also detected in lighttpd. Either triggers an explicit abort() by lighttpd. This is not exploitable beyond triggering the explicit abort() with subsequent application exit.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Forced Integer Overflow This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.
References
- http://www.securityfocus.com/bid/107907
- http://www.securityfocus.com/bid/107907
- https://github.com/lighttpd/lighttpd1.4/commit/32120d5b8b3203fc21ccb9eafb0eaf824bb59354
- https://github.com/lighttpd/lighttpd1.4/commit/32120d5b8b3203fc21ccb9eafb0eaf824bb59354
- https://redmine.lighttpd.net/issues/2945
- https://redmine.lighttpd.net/issues/2945