Moderate
CVE-2019-12256 - VxWorks IPv4 Options Buffer Overflow
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Description
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Type
Moderate
(2 users assessed)
Moderate
(2 users assessed)Unknown
Unknown
Unknown
CVE-2019-12256 - VxWorks IPv4 Options Buffer Overflow
MITRE ATT&CK
Collection
Command and Control
Credential Access
Defense Evasion
Discovery
Execution
Exfiltration
Impact
Initial Access
Lateral Movement
Persistence
Privilege Escalation
Description
This vulnerability can be triggered by a specially crafted IP packet sent to the target device, even as a broadcast or multicast packet. It does not require any specific application or configuration to be running on the device, and it affects any device running VxWorks v6.9.4 or above with a network connection. The vulnerability causes a stack overflow in the handling of IP options in the IPv4 header, making it easy to reach RCE by it.
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Ratings
-
Attacker ValueVery Low
-
ExploitabilityVery Low
Technical Analysis
Capability problems with exploitation: an attacker needs a payload to do something other than a DoS. Shellcode for embedded OSes like this needs to be customized for each firmware version and device, which causes problems. This significantly increases the cost for an attacker to do something other than a DoS since it has to be customized to the target. High utility for an advanced actor who has the capability to develop custom payloads and a particular target in mind. Low utility for a low-skilled actor who wants to ‘spray and pray’.
Mitigations: folks should limit opportunities by having strong malformed-packet filtering at the network level. Routers and switches should not be based on VxWorks at the edge.
https://www.blackhat.com/presentations/bh-usa-09/LINDNER/BHUSA09-Lindner-RouterExploit-SLIDES.pdf
Another interesting issue with this vulnerability lies around getting the malformed packets from the edge of a network into the core of the target device. Each device needs independent analysis to determine the risk. An edge device would be riskier than a core, one. In this particular case, it’s really surprising however that VxWorks did not just isic, which has been around for years and years to find a vulnerability like this: http://isic.sourceforge.net/
Note: when validating the Urgent/11 scanner here: https://github.com/ArmisSecurity/urgent11-detector we found that it was unlikely to be effective across even a minimal security boundary of a standard router between network segments. We had a hard time testing it since the malformed packets were discarded by several commodity and not specially-configured kit.
Ratings
-
Attacker ValueVery High
-
ExploitabilityHigh
Technical Analysis
Simply sending a malformed packet can result in RCE on a device running VxWorks, and there are reportedly no features such as ASLR, DEP, etc. enabled to mitigate the issue. Given the simplicity of successful exploitation, I’d say that this is a vulnerability to take seriously and patch.
Any of the others stand out? https://www.armis.com/urgent11/
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Technical Analysis
Report as Exploited in the Wild
What do we mean by "exploited in the wild"?
By selecting this, you are verifying to the AttackerKB community that either you, or a reputable source (example: a security vendor or researcher), has observed an active attempt by attackers, or IOCs related, to exploit this vulnerability outside of a research environment.
A vulnerability should also be considered "exploited in the wild" if there is a publicly available PoC or exploit (example: in an exploitation framework like Metasploit).
