CVE-2017-1000112

high-risk
Published 2017-10-05

Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ("[IPv4/IPv6]: UFO Scatter-gather approach") on Oct 18 2005.

Do I need to act?

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84.5% chance of exploitation in next 30 days
EPSS score — higher than 16% of all CVEs
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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3 public exploits available
45147, 43418, 47169
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.0/10 High
LOCAL / HIGH complexity

Affected Products (1)

Affected Vendors

Linux

References (26)

Mailing List http://seclists.org/oss-sec/2017/q3/277
Third Party Advisory http://www.debian.org/security/2017/dsa-3981
Third Party Advisory http://www.securityfocus.com/bid/100262
Third Party Advisory http://www.securitytracker.com/id/1039162
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2918
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2930
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2931
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:3200
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:1931
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:1932
Third Party Advisory https://access.redhat.com/errata/RHSA-2019:4159
Third Party Advisory https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-1000112
Third Party Advisory https://www.exploit-db.com/exploits/45147/
Mailing List http://seclists.org/oss-sec/2017/q3/277
Third Party Advisory http://www.debian.org/security/2017/dsa-3981
Third Party Advisory http://www.securityfocus.com/bid/100262
Third Party Advisory http://www.securitytracker.com/id/1039162
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2918
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2930
Third Party Advisory https://access.redhat.com/errata/RHSA-2017:2931
and 6 more references
50
/ 100
high-risk
Severity 18/34 · Moderate
Exploitability 27/34 · High
Exposure 5/34 · Minimal