ASA-2019-00506 – Wind River VxWorks: TCP Urgent Pointer = 0 leads to integer underflow


Allele Security Alert

ASA-2019-00506

Identifier(s)

ASA-2019-00506, CVE-2019-12255, VXW6-87100

Title

TCP Urgent Pointer = 0 leads to integer underflow

Vendor(s)

Wind River

Product(s)

Wind River VxWorks

Affected version(s)

Wind River VxWorks 6 version 6.6
Wind River VxWorks 6 version 6.7
Wind River VxWorks 6 version 6.8
Wind River VxWorks 6 versions 6.9.x before 6.9.4

Fixed version(s)

Wind River VxWorks 6 version 6.9.4

Proof of concept

Yes

Description

A specially crafted TCP-segment with the URG-flag set may cause overflow of the buffer passed to recv(), recvfrom() or recvmsg() socket routines.

With a prerequisite that the system uses TCP sockets, an attacker can either hijack an existing TCP session and inject bad TCP segments, or establish a new TCP session on any TCP port the victim system listens to. The impact of the vulnerability is a buffer overflow of up to a full TCP receive-windows (by default 10k-64k depending on the version). The buffer overflow happens in the task calling recv()/recvfrom()/recvmsg(). Applications that pass a buffer equal to or larger than a full TCP window are not susceptible to this attack. Applications passing a stack-allocated variable as buffer are the easiest to exploit. The most likely outcome is a crash of the application reading from the affected socket. In the worst-case scenario, this vulnerability can potentially lead to RCE.

Technical details

Unknown

Credits

Ben Seri (Armis Labs)

Reference(s)

SECURITY ADVISORY: WIND RIVER TCP/IP STACK (IPNET) VULNERABILITIES
https://www.windriver.com/security/announcements/tcp-ip-network-stack-ipnet-urgent11/security-advisory-ipnet/security-advisory-ipnet.pdf

SECURITY VULNERABILITY RESPONSE INFORMATION – TCP/IP Network Stack (IPnet, Urgent/11)
https://www.windriver.com/security/announcements/tcp-ip-network-stack-ipnet-urgent11/

CVE: CVE-2019-12255 - Wind River Support Network
https://support2.windriver.com/index.php?page=cve&on=view&id=CVE-2019-12255

URGENT/11 Information from the Research Team – Armis Labs
https://armis.com/urgent11/

Critical vulnerabilities to remotely compromise VxWorks, the most popular RTOS
https://go.armis.com/hubfs/White-papers/Urgent11%20Technical%20White%20Paper.pdf

Critical Zero Days Remotely Compromise the Most Popular Real-Time OS
https://i.blackhat.com/USA-19/Thursday/us-19-Seri-Critical-Zero-Days-Remotely-Compromise-The-Most-Popular-Real-Time-OS.pdf

CVE-2019-12255
https://github.com/dazhouzhou/vxworks-poc/tree/master/CVE-2019-12255

CVE-2019-12255
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12255

CVE-2019-12255
https://nvd.nist.gov/vuln/detail/CVE-2019-12255

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Last modified: August 15, 2019

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