Linux Kernel __ip_append_data Packet race condition

CVSS Meta Temp Score
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CTI Interest Score
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6.1$0-$5k0.00

A vulnerability, which was classified as critical, was found in Linux Kernel (Operating System) (affected version unknown). Affected is the function __ip_append_data. The manipulation as part of a Packet leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The bug was discovered 08/10/2017. The weakness was disclosed 10/05/2017 by Andrey Konovalov as not defined mailinglist post (oss-sec). The advisory is shared for download at seclists.org. This vulnerability is traded as CVE-2017-1000112 since 10/03/2017. The attack needs to be approached locally. The exploitation doesn't require any form of authentication. Technical details and a public exploit are known.

A public exploit has been developed by bcoles in C. The exploit is shared for download at github.com. It is declared as highly functional. The vulnerability was handled as a non-public zero-day exploit for at least 1 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 102367 (Amazon Linux AMI : kernel (ALAS-2017-868)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Amazon Linux Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 351447 (Amazon Linux Security Advisory for kernel: ALAC2012-2018-013).

Upgrading eliminates this vulnerability. A possible mitigation has been published 3 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (102367) and Exploit-DB (47169). The entries 102802, 103034, 104449 and 104864 are pretty similar.

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CPE 2.3info

CPE 2.2info

CVSSv4info

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CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.9
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.0
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Race condition
CWE: CWE-362
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Access: Public
Status: Highly functional
Author: bcoles
Programming Language: 🔍
Download: 🔍

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Nessus ID: 102367
Nessus Name: Amazon Linux AMI : kernel (ALAS-2017-868)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 53754
OpenVAS Name: Debian Security Advisory DSA 3981-1 (linux - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

MetaSploit ID: ufo_privilege_escalation.rb
MetaSploit Name: Linux Kernel UDP Fragmentation Offset (UFO) Privilege Escalation
MetaSploit File: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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Timelineinfo

08/10/2017 🔍
08/10/2017 +0 days 🔍
08/11/2017 +1 days 🔍
10/03/2017 +53 days 🔍
10/04/2017 +1 days 🔍
10/05/2017 +1 days 🔍
10/05/2017 +0 days 🔍
10/26/2017 +21 days 🔍
12/30/2022 +1891 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: RHSA-2017:2918
Researcher: Andrey Konovalov
Status: Not defined

CVE: CVE-2017-1000112 (🔍)
OVAL: 🔍

SecurityTracker: 1039162
SecurityFocus: 100262 - Linux Kernel CVE-2017-1000112 Local Memory Corruption Vulnerability

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 10/05/2017 15:13
Updated: 12/30/2022 17:00
Changes: 10/05/2017 15:13 (77), 07/26/2019 14:38 (4), 07/26/2019 14:39 (2), 07/13/2020 09:53 (9), 01/15/2021 13:37 (6), 12/30/2022 17:00 (3)
Complete: 🔍
Committer: misc

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