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Fix MSSQL log parser bug #1393

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Fix MSSQL log parser bug #1393

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0be213e
Fix MSSQL log parsing bug
qmadev Nov 10, 2025
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qmadev Nov 10, 2025
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Merge branch 'main' into fix/mssql-errorlog
qmadev Nov 23, 2025
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Merge branch 'main' into fix/mssql-errorlog
qmadev Dec 4, 2025
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27 changes: 23 additions & 4 deletions dissect/target/plugins/os/windows/log/mssql.py
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Original file line number Diff line number Diff line change
Expand Up @@ -81,19 +81,38 @@ def errorlog(self) -> Iterator[MssqlErrorlogRecord]:
buf = ""

for line in fh:
if ts := RE_TIMESTAMP_PATTERN.match(line):
# If we have a buffer with a timestamp and
# our current line also has a timestamp,
# we should have a complete record in our buffer.
if previous_ts := RE_TIMESTAMP_PATTERN.match(buf):
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@twiggler twiggler Nov 20, 2025 •
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This potentially causes memory exhaustion if the log file does not start with a timestamp.
(And no entries will get returned)

I think the logic I posted here does not suffer from that problem

if current_ts := RE_TIMESTAMP_PATTERN.match(line):
yield MssqlErrorlogRecord(
ts=datetime.strptime(previous_ts.group(), "%Y-%m-%d %H:%M:%S.%f").replace(tzinfo=timezone.utc),
instance=instance,
# The process name is a fixed-width field and is always 12 characters long.
process=buf[23:35].strip(),
message=buf[35:].strip(),
path=errorlog,
_target=self.target,
)

buf = ""

buf += line

# For the last line
if buf:
if current_ts := RE_TIMESTAMP_PATTERN.match(line):
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@twiggler twiggler Nov 20, 2025

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This only works if the last line is timestamped. If it is text, it will fail and the last record will be dropped.

The solution is to use current_ts

yield MssqlErrorlogRecord(
ts=datetime.strptime(ts.group(), "%Y-%m-%d %H:%M:%S.%f").replace(tzinfo=timezone.utc),
ts=datetime.strptime(current_ts.group(), "%Y-%m-%d %H:%M:%S.%f").replace(tzinfo=timezone.utc),
instance=instance,
# The process name is a fixed-width field and is always 12 characters long.
process=buf[23:35].strip(),
message=buf[35:].strip(),
path=errorlog,
_target=self.target,
)
buf = ""

buf += line

def _find_instances(self) -> set[str, TargetPath]:
return {
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