A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.
[
{
"id": "CVE-2018-20217-2b9be4ce",
"signature_type": "Function",
"signature_version": "v1",
"digest": {
"length": 2237.0,
"function_hash": "281632458950095218231934864773643278513"
},
"target": {
"function": "kdc_process_s4u2self_req",
"file": "src/kdc/kdc_util.c"
},
"source": "https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086",
"deprecated": false
},
{
"id": "CVE-2018-20217-9deb1157",
"signature_type": "Function",
"signature_version": "v1",
"digest": {
"length": 1519.0,
"function_hash": "22009747526011531247411191432701765815"
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"target": {
"function": "s4u_identify_user",
"file": "src/lib/krb5/krb/s4u_creds.c"
},
"source": "https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086",
"deprecated": false
},
{
"id": "CVE-2018-20217-b4599e87",
"signature_type": "Line",
"signature_version": "v1",
"digest": {
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"threshold": 0.9
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"target": {
"file": "src/kdc/kdc_util.c"
},
"source": "https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086",
"deprecated": false
},
{
"id": "CVE-2018-20217-e4d34f09",
"signature_type": "Line",
"signature_version": "v1",
"digest": {
"line_hashes": [
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"threshold": 0.9
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"target": {
"file": "src/lib/krb5/krb/s4u_creds.c"
},
"source": "https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086",
"deprecated": false
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]