2023-7-11 20:30:0 Author: www.kitploit.com(查看原文) 阅读量:23 收藏
YARA rules can be syntactically correct but still dysfunctional. yaraQA tries to find and report these issues to the author or maintainer of a YARA rule set.
I'm going to extend the test set over time. Each minor version will include new features or new tests.
Use a baseline to only see new issues (not the ones that you've already reviewed). The baseline file is an old JSON output of a reviewed state.
Example rules with issues can be found in the ./test folder.
binary 0 in front or a space after the string). Every additional byte helps." }, { "rule": "Demo_Rule_3_Fullword_FilePath_Section", "id": "SM3", "issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backslashes and thus the modifier could lead to a dysfunctional rule.", "element": { "name": "$s1", "value": "\\\\ZombieBoy\\\\", "type": "text", "modifiers": [ "ascii", "fullword" ] }, "level": "warning", "type": "logic", "recommendation": "Remove the 'fullword' modifier" }, { "rule": "Demo_Rule_4_Condition_Never_Matches", "id": "CE1", "issue": "The rule uses a condition that will never match", "element": { "condition_segment": "2 of", "num_of_strings": 1 }, "level": "error", "type": "logic", "recommendation": "Fix the condition" }, { "rule": "Demo_Rule_5_Condition_Short_String_At_Pos", "id": "PA1", "issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.", "element": { "condition_segment": "$mz at 0", "string": "$mz", "value": "MZ" }, "level": "warning", "type": "performance", "recommendation": "" }, { "rule": "Demo_Rule_5_Condition_Short_String_At_Pos", "id": "PA2", "issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.", "element": { "name": "$mz", "value": "MZ", "type": "text", "modifiers": [ "ascii" ] }, "level": "warning", "type": "performance", "recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps." }, { "rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos", "id": "PA1", "issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.", "element": { "condition_segment": "$mz at 0", "string": "$mz", "value": "{ 4d 5a }" }, "level": "warning", "type": "performance", "recommendation": "" }, { "rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos", "id": "PA2", "issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.", "element": { "name": "$mz", "value": "{ 4d 5a }", "type": "byte" }, "level": "warning", "type": "performance", "recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps." }, { "rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos", "id": "SM3", "issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backslashes and thus the modifier could lead to a dysfunctional rule.", "element": { "name": "$s1", "value": "\\\\Section\\\\in\\\\Path\\\\", "type": "text", "modifiers": [ "ascii", "fullword" ] }, "level": "warning", "type": "logic", "recommendation": "Remove the 'fullword' modifier" } ]" dir="auto">
[
{
"rule": "Demo_Rule_1_Fullword_PDB",
"id": "SM1",
"issue": "The rule uses a PDB string with the modifier 'wide'. PDB strings are always included as ASCII strings. The 'wide' keyword is unneeded.",
"element": {
"name": "$s1",
"value": "\\\\i386\\\\mimidrv.pdb",
"type": "text",
"modifiers": [
"ascii",
"wide",
"fullword"
]
},
"level": "info",
"type": "logic",
"recommendation": "Remove the 'wide' modifier"
},
{
"rule": "Demo_Rule_1_Fullword_PDB",
"id": "SM2",
"issue": "The rule uses a PDB string with the modifier 'fullword' but it starts with two backslashes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": " $s1",
"value": "\\\\i386\\\\mimidrv.pdb",
"type": "text",
"modifiers": [
"ascii",
"wide",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
},
{
"rule": "Demo_Rule_2_Short_Atom",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",
"element": {
"name": "$s1",
"value": "{ 01 02 03 }",
"type": "byte"
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_3_Fullword_FilePath_Section",
"id": "SM3",
"issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backslashes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": "$s1",
"value": "\\\\ZombieBoy\\\\",
"type": "text",
"modifiers": [
"ascii",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
},
{
"rule": "Demo_Rule_4_Condition_Never_Matches",
"id": "CE1",
"issue": "The rule uses a condition that will never match",
"element": {
"condition_segment": "2 of",
"num_of_strings": 1
},
"level": "error",
"type": "logic",
"recommendation": "Fix the condition"
},
{
"rule": "Demo_Rule_5_Condition_Short_String_At_Pos",
"id": "PA1",
"issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.",
"element": {
"condition_segment": "$mz at 0",
"string": "$mz",
"value": "MZ"
},
"level": "warning",
"type": "performance",
"recommendation": ""
},
{
"rule": "Demo_Rule_5_Condition_Short_String_At_Pos",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",< br/> "element": {
"name": "$mz",
"value": "MZ",
"type": "text",
"modifiers": [
"ascii"
]
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "PA1",
"issue": "This rule looks for a short string at a particular position. A short string represents a short atom and could be rewritten to an expression using uint(x) at position.",
"element": {
"condition_segment": "$mz at 0",
"string": "$mz",
"value": "{ 4d 5a }"
},
"level": "warning",
"type": "performance",
"recommendation": ""
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "PA2",
"issue": "The rule contains a string that turns out to be a very short atom, which could cause a reduced performance of the complete rule set or increased memory usage.",
"element": {
"name": "$mz",
"value": "{ 4d 5a }",
"type": "byte"
},
"level": "warning",
"type": "performance",
"recommendation": "Try to avoid using such short atoms, by e.g. adding a few more bytes to the beginning or the end (e.g. add a binary 0 in front or a space after the string). Every additional byte helps."
},
{
"rule": "Demo_Rule_6_Condition_Short_Byte_At_Pos",
"id": "SM3",
"issue": "The rule uses a string with the modifier 'fullword' but it starts and ends with two backsla shes and thus the modifier could lead to a dysfunctional rule.",
"element": {
"name": "$s1",
"value": "\\\\Section\\\\in\\\\Path\\\\",
"type": "text",
"modifiers": [
"ascii",
"fullword"
]
},
"level": "warning",
"type": "logic",
"recommendation": "Remove the 'fullword' modifier"
}
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