CVE-2023-36478

Eclipse Jetty provides a web server and servlet container. In versions 11.0.0 through 11.0.15, 10.0.0 through 10.0.15, and 9.0.0 through 9.4.52, an integer overflow in MetaDataBuilder.checkSize allows for HTTP/2 HPACK header values to exceed their size limit. MetaDataBuilder.java determines if a header name or value exceeds the size limit, and throws an exception if the limit is exceeded. However, when length is very large and huffman is true, the multiplication by 4 in line 295 will overflow, and length will become negative. (_size+length) will now be negative, and the check on line 296 will not be triggered. Furthermore, MetaDataBuilder.checkSize allows for user-entered HPACK header value sizes to be negative, potentially leading to a very large buffer allocation later on when the user-entered size is multiplied by 2. This means that if a user provides a negative length value (or, more precisely, a length value which, when multiplied by the 4/3 fudge factor, is negative), and this length value is a very large positive number when multiplied by 2, then the user can cause a very large buffer to be allocated on the server. Users of HTTP/2 can be impacted by a remote denial of service attack. The issue has been fixed in versions 11.0.16, 10.0.16, and 9.4.53. There are no known workarounds.

Weakness

The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.

Affected Software

Potential Mitigations

• Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• If possible, choose a language or compiler that performs automatic bounds checking.
• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• Use libraries or frameworks that make it easier to handle numbers without unexpected consequences.
• Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++). [REF-106]
• Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
• Use unsigned integers where possible. This makes it easier to perform validation for integer overflows. When signed integers are required, ensure that the range check includes minimum values as well as maximum values.
• Understand the programming language’s underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, “not-a-number” calculations, and how the language handles numbers that are too large or too small for its underlying representation. [REF-7]
• Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/92.html

References

• http://www.openwall.com/lists/oss-security/2023/10/18/4
• https://github.com/eclipse/jetty.project/pull/9634
• https://github.com/eclipse/jetty.project/releases/tag/jetty-10.0.16
• https://github.com/eclipse/jetty.project/releases/tag/jetty-11.0.16
• https://github.com/eclipse/jetty.project/releases/tag/jetty-9.4.53.v20231009
• https://github.com/eclipse/jetty.project/security/advisories/GHSA-wgh7-54f2-x98r
• https://lists.debian.org/debian-lts-announce/2023/10/msg00045.html
• https://security.netapp.com/advisory/ntap-20231116-0011/
• https://www.debian.org/security/2023/dsa-5540