(Note that either workaround should be sufficient on its own.
Workaround #2: Disable SACK processing ( /proc/sys/net/ipv4/tcp_sack set to 0). Also, note that this mitigation is only effective if TCP probing is disabled (that is, the _mtu_probing sysctl is set to 0, which appears to be the default value for that sysctl). You can apply a higher or lower limit, as appropriate for your environment.) Note that these filters may break legitimate connections which rely on a low MSS. Workaround #1: Block connections with a low MSS using one of the supplied filters.
PARTY PANIC REMOTE PLAY PATCH
Additionally, versions of the Linux kernel up to, and including, 4.14 require a second patch PATCH_net_1a.patch. Details: 1: CVE-2019-11477: SACK Panic (Linux >= 2.6.29)Ī sequence of SACKs may be crafted such that one can trigger an integer overflow, leading to a kernel panic.įix: Apply the patch PATCH_net_1_4.patch. We recommend that affected parties enact one of those described below, based on their environment.
If patches can not be applied, certain mitigations will be effective. There are patches that address most of these vulnerabilities. The most serious, dubbed “SACK Panic,” allows a remotely-triggered kernel panic on recent Linux kernels. The vulnerabilities specifically relate to the Maximum Segment Size (MSS) and TCP Selective Acknowledgement (SACK) capabilities. Netflix has identified several TCP networking vulnerabilities in FreeBSD and Linux kernels. Advisory ID: NFLX-2019-001 Title: Linux and FreeBSD Kernel: Multiple TCP-based remote denial of service vulnerabilities Release Date: Severity: Critical Overview:
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