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[critical] fix: [export_mod] sanitize CSV values against formula injection #891

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[critical] fix: [export_mod] sanitize CSV values against formula injection #891

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16 changes: 12 additions & 4 deletions misp_modules/modules/export_mod/threatStream_misp_export.py
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,14 @@
mispattributes = {"input": list(fieldmap.keys())}


def sanitize_csv_value(value):
"""Prefix values that could be interpreted as spreadsheet formulas to prevent CSV injection."""
value = str(value)
if value.startswith(("=", "+", "-", "@")):
value = "'" + value
return value


def handler(q=False):
"""
Convert a MISP query into a CSV file matching the ThreatStream Structured Import file format.
Expand Down Expand Up @@ -80,17 +88,17 @@ def handler(q=False):
for i, indicator in enumerate(indicators):
writer.writerow(
{
"value": indicator,
"value": sanitize_csv_value(indicator),
"itype": ts_types[i],
"tags": attribute["comment"],
"tags": sanitize_csv_value(attribute["comment"]),
}
)
else:
writer.writerow(
{
"itype": fieldmap[attribute["type"]],
"value": attribute["value"],
"tags": attribute["comment"],
"value": sanitize_csv_value(attribute["value"]),
"tags": sanitize_csv_value(attribute["comment"]),
}
)

Expand Down
16 changes: 12 additions & 4 deletions misp_modules/modules/export_mod/threat_connect_export.py
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,14 @@
mispattributes = {"input": list(fieldmap.keys())}


def sanitize_csv_value(value):
"""Prefix values that could be interpreted as spreadsheet formulas to prevent CSV injection."""
value = str(value)
if value.startswith(("=", "+", "-", "@")):
value = "'" + value
return value


def handler(q=False):
"""
Convert a MISP query into a CSV file matching the ThreatConnect Structured Import file format.
Expand Down Expand Up @@ -90,18 +98,18 @@ def handler(q=False):
writer.writerow(
{
"Type": tc_types[i],
"Value": indicator,
"Value": sanitize_csv_value(indicator),
"Source": config["Default_Source"],
"Description": attribute["comment"],
"Description": sanitize_csv_value(attribute["comment"]),
}
)
else:
writer.writerow(
{
"Type": fieldmap[attribute["type"]],
"Value": attribute["value"],
"Value": sanitize_csv_value(attribute["value"]),
"Source": config["Default_Source"],
"Description": attribute["comment"],
"Description": sanitize_csv_value(attribute["comment"]),
}
)

Expand Down