Vulnerability Details : CVE-2017-6657
Cisco Sourcefire Snort 3.0 before build 233 mishandles Ether Type Validation. Since valid ether type and IP protocol numbers do not overlap, Snort++ stores all protocol decoders in a single array. That makes it possible to craft packets that have IP protocol numbers in the ether type field which will confuse the Snort++ decoder. For example, an eth:llc:snap:icmp6 packet will cause a crash because there is no ip6 header with which to calculate the icmp6 checksum. Affected decoders include gre, llc, trans_bridge, ciscometadata, linux_sll, and token_ring. The fix adds a check in the packet manager to validate the ether type before indexing the decoder array. An out of range ether type will raise 116:473.
Exploit prediction scoring system (EPSS) score for CVE-2017-6657
Probability of exploitation activity in the next 30 days: 0.12%
Percentile, the proportion of vulnerabilities that are scored at or less: ~ 45 % EPSS Score History EPSS FAQ
CVSS scores for CVE-2017-6657
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source |
---|---|---|---|---|---|
5.0
|
MEDIUM | AV:N/AC:L/Au:N/C:N/I:N/A:P |
10.0
|
2.9
|
NIST |
7.5
|
HIGH | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
3.9
|
3.6
|
NIST |
References for CVE-2017-6657
-
http://blog.snort.org/2017/05/snort-vulnerabilities-found.html
Snort Blog: Snort++ Vulnerabilities FoundThird Party Advisory
-
http://www.securitytracker.com/id/1038483
Cisco Snort++ Protocol Decoder Bugs Let Remote Users Deny Service - SecurityTracker
-
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170515-snort
Cisco Snort++ Protocol Decoder Denial of Service VulnerabilitiesVendor Advisory
Products affected by CVE-2017-6657
- cpe:2.3:a:cisco:snort\+\+:-:*:*:*:*:*:*:*