ALAS-2019-1299

Related Vulnerabilities: CVE-2019-9511   CVE-2019-9513   CVE-2019-9516  

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both. (CVE-2019-9511) Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU. (CVE-2019-9513) Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory. (CVE-2019-9516)

ALAS-2019-1299


Amazon Linux AMI Security Advisory: ALAS-2019-1299
Advisory Release Date: 2019-09-30 21:06 Pacific
Advisory Updated Date: 2019-10-02 22:58 Pacific
Severity: Important

Issue Overview:

Some HTTP/2 implementations are vulnerable to window size manipulation and stream prioritization manipulation, potentially leading to a denial of service. The attacker requests a large amount of data from a specified resource over multiple streams. They manipulate window size and stream priority to force the server to queue the data in 1-byte chunks. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both. (CVE-2019-9511)

Some HTTP/2 implementations are vulnerable to resource loops, potentially leading to a denial of service. The attacker creates multiple request streams and continually shuffles the priority of the streams in a way that causes substantial churn to the priority tree. This can consume excess CPU. (CVE-2019-9513)

Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory. (CVE-2019-9516)


Affected Packages:

nginx


Issue Correction:
Run yum update nginx to update your system.

New Packages:
i686:
    nginx-mod-stream-1.16.1-1.37.amzn1.i686
    nginx-all-modules-1.16.1-1.37.amzn1.i686
    nginx-mod-http-xslt-filter-1.16.1-1.37.amzn1.i686
    nginx-mod-http-image-filter-1.16.1-1.37.amzn1.i686
    nginx-1.16.1-1.37.amzn1.i686
    nginx-mod-http-geoip-1.16.1-1.37.amzn1.i686
    nginx-mod-mail-1.16.1-1.37.amzn1.i686
    nginx-mod-http-perl-1.16.1-1.37.amzn1.i686
    nginx-debuginfo-1.16.1-1.37.amzn1.i686

src:
    nginx-1.16.1-1.37.amzn1.src

x86_64:
    nginx-mod-http-image-filter-1.16.1-1.37.amzn1.x86_64
    nginx-mod-mail-1.16.1-1.37.amzn1.x86_64
    nginx-mod-stream-1.16.1-1.37.amzn1.x86_64
    nginx-debuginfo-1.16.1-1.37.amzn1.x86_64
    nginx-1.16.1-1.37.amzn1.x86_64
    nginx-mod-http-perl-1.16.1-1.37.amzn1.x86_64
    nginx-mod-http-geoip-1.16.1-1.37.amzn1.x86_64
    nginx-all-modules-1.16.1-1.37.amzn1.x86_64
    nginx-mod-http-xslt-filter-1.16.1-1.37.amzn1.x86_64