A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. When the user doesn't exist PAM try to authenticate with root and in the case of an empty password it successfully authenticate.
[
{
"signature_version": "v1",
"source": "https://github.com/linux-pam/linux-pam/commit/225f17470eed9f44282f435ad1ed64c94d9a2ddf",
"deprecated": false,
"target": {
"file": "modules/pam_unix/bigcrypt.c"
},
"id": "CVE-2020-27780-90a0a465",
"signature_type": "Line",
"digest": {
"threshold": 0.9,
"line_hashes": [
"236274917370666437465787812312716913764",
"191165804437170388625080527033927485485",
"248212176959400049713618959841331975794",
"74187730262540881415256141112760525222",
"53241490001132424225404146543772968193",
"169694962436386515826333909717745520461",
"339114646913897635961686157876483083914",
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]
}
},
{
"signature_version": "v1",
"source": "https://github.com/linux-pam/linux-pam/commit/225f17470eed9f44282f435ad1ed64c94d9a2ddf",
"deprecated": false,
"target": {
"file": "modules/pam_unix/bigcrypt.c",
"function": "bigcrypt"
},
"id": "CVE-2020-27780-febf053a",
"signature_type": "Function",
"digest": {
"function_hash": "251657082591479008743931529537448873642",
"length": 1660.0
}
}
]