Update analysers (WIP)

aperisolve/analyzers/binwalk.py

@@ -3,75 +3,27 @@
 # mypy: disable-error-code=unused-awaitable
 """Binwalk Analyzer for Image Submissions."""
 
-import shutil
-import subprocess
 from pathlib import Path
-from typing import Any
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class BinwalkAnalyzer(SubprocessAnalyzer):
+    """Analyzer for binwalk."""
+
+    def __init__(self, *args):
+        super().__init__("binwalk", *args, has_archive=True)
+        self.cmd = ["binwalk", "--matryoshka", "-e", self.img, "--run-as=root"]
+        self.make_folder = False  # Binwalk already create its own folder
+
+    def get_extracted_dir(self) -> Path:
+        return self.output_dir / f"_{self.input_img.name}.extracted"
+
+    def is_error(self, returncode: int, stdout: str, stderr: str, zip_exist: bool) -> bool:
+        return len(stderr) > 0 and not zip_exist and False
 
 
 def analyze_binwalk(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using binwalk."""
-
+    analyzer = BinwalkAnalyzer(input_img, output_dir)
-    image_name = input_img.name
+    analyzer.analyze()
-    extracted_dir = output_dir / f"_{image_name}.extracted"
-
-    try:
-        stderr = ""
-        # Run binwalk
-        data = subprocess.run(
-            ["binwalk", "--matryoshka", "-e", "../" + str(image_name), "--run-as=root"],
-            cwd=output_dir,
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        stderr += data.stderr
-
-        zip_exist = False
-        if extracted_dir.exists():
-            # Zip extracted files
-            zip_data = subprocess.run(
-                ["7z", "a", "../binwalk.7z", "*"],
-                cwd=extracted_dir,
-                capture_output=True,
-                text=True,
-                check=False,
-                timeout=MAX_PENDING_TIME,
-            )
-            zip_exist = True
-            stderr += zip_data.stderr
-
-        # Remove the extracted directory
-        if extracted_dir.exists():
-            shutil.rmtree(extracted_dir)
-
-        # Only report error if stderr exists AND extraction failed.
-        # If zip_exist is True, binwalk worked (despite warnings), so we proceed.
-        if len(stderr) > 0 and not zip_exist:
-            err: dict[str, dict[str, Any]] = {
-                "binwalk": {
-                    "status": "error",
-                    "output": data.stdout.split("\n") if data else [],
-                    "error": stderr,
-                }
-            }
-            update_data(output_dir, err)
-            return None
-
-        output_data: dict[str, dict[str, Any]] = {
-            "binwalk": {
-                "status": "ok",
-                "output": data.stdout.split("\n") if data else [],
-            }
-        }
-        if zip_exist:
-            output_data["binwalk"]["download"] = f"/download/{output_dir.name}/binwalk"
-
-        update_data(output_dir, output_data)
-
-    except Exception as e:
-        update_data(output_dir, {"binwalk": {"status": "error", "error": str(e)}})
-    return None

aperisolve/analyzers/exiftool.py

@@ -3,46 +3,29 @@
 # mypy: disable-error-code=unused-awaitable
 """Exiftool Analyzer for Image Submissions."""
 
-import subprocess
 from pathlib import Path
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class ExiftoolAnalyzer(SubprocessAnalyzer):
+    """Analyzer for exiftool."""
+
+    def __init__(self, *args):
+        super().__init__("exiftool", *args)
+        self.cmd = ["exiftool", "-a", "-u", "-g1", self.img]
+
+    def process_output(self, stdout: str, stderr: str) -> dict[str, str]:
+        """Process the stdout into a list of lines."""
+        metadata: dict[str, str] = {}
+        for line in stdout.split("\n"):
+            if ":" in line:
+                key, value = line.split(":", 1)
+                metadata[key.strip()] = value.strip()
+        return metadata
 
 
 def analyze_exiftool(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using exiftool."""
-
+    analyzer = ExiftoolAnalyzer(input_img, output_dir)
-    try:
+    analyzer.analyze()
-        data = subprocess.run(
-            ["exiftool", input_img],
-            capture_output=True,
-            text=True,
-            check=True,
-            timeout=MAX_PENDING_TIME,
-        )
-
-        metadata: dict[str, str] = {}
-        for line in data.stdout.split("\n"):
-            if ":" in line:
-                key, value = line.split(":", 1)
-                metadata[key.strip()] = value.strip()
-
-        if data.stderr:
-            update_data(
-                output_dir,
-                {
-                    "exiftool": {
-                        "status": "error",
-                        "output": metadata,
-                        "error": data.stderr,
-                    }
-                },
-            )
-            return
-
-        update_data(
-            output_dir,
-            {"exiftool": {"status": "ok", "output": metadata}},
-        )
-    except Exception as e:
-        update_data(output_dir, {"exiftool": {"status": "error", "error": str(e)}})

aperisolve/analyzers/foremost.py

@@ -3,60 +3,30 @@
 # mypy: disable-error-code=unused-awaitable
 """Foremost Analyzer for Image Submissions."""
 
-import shutil
-import subprocess
 from pathlib import Path
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class ForemostAnalyzer(SubprocessAnalyzer):
+    """Analyzer for foremost."""
+
+    def __init__(self, *args):
+        super().__init__("foremost", *args, has_archive=True)
+        self.cmd = ["foremost", "-o", str(self.get_extracted_dir()), "-i", self.img]
+
+    def is_error(self, returncode: int, stdout: str, stderr: str, zip_exist: bool) -> bool:
+        """Check if the result is an error."""
+        return len(stderr) > 60
+
+    def process_output(self, stdout: str, stderr: str) -> str | list[str] | dict[str, str]:
+        """Process the stdout/stderr."""
+        if "Processing" in stderr and "|*|" in stderr:
+            return stderr.strip().split("\n")
+        return []
 
 
 def analyze_foremost(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using foremost."""
-
+    analyzer = ForemostAnalyzer(input_img, output_dir)
-    try:
+    analyzer.analyze()
-        foremost_dir = output_dir / "foremost"
-        foremost_dir.mkdir(parents=True, exist_ok=True)
-
-        stderr = ""
-        # Run foremost
-        data = subprocess.run(
-            ["foremost", "-o", foremost_dir, "-i", input_img],
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        # Note: foremost use stderr as standard output for results :o)
-        # So we can't use it as error detection :
-        # stderr += data.stderr
-
-        # Zip extracted files
-        zip_data = subprocess.run(
-            ["7z", "a", "../foremost.7z", "*"],
-            cwd=foremost_dir,
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-
-        stderr += zip_data.stderr
-
-        # Remove the extracted directory
-        shutil.rmtree(foremost_dir)
-
-        data_strings = data.stdout.split("\n") if data else []
-        data_strings = [s for s in data_strings if s]
-
-        update_data(
-            output_dir,
-            {
-                "foremost": {
-                    "status": "ok",
-                    "output": data_strings,
-                    "download": f"/download/{output_dir.name}/foremost",
-                }
-            },
-        )
-    except Exception as e:
-        update_data(output_dir, {"foremost": {"status": "error", "error": str(e)}})

aperisolve/analyzers/outguess.py

@@ -3,97 +3,32 @@
 # mypy: disable-error-code=unused-awaitable
 """Outguess Analyzer for Image Submissions."""
 
-import shutil
-import subprocess
 from pathlib import Path
 from typing import Optional
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
 
 
-def analyze_outguess(
+class OutguessAnalyzer(SubprocessAnalyzer):
-    input_img: Path, output_dir: Path, password: Optional[str] = None
+    """Analyzer for outguess."""
-) -> None:
-    """Analyze an image submission using outguess."""
 
-    image_name = input_img.name
+    def __init__(self, *args):
-    try:
+        super().__init__("outguess", *args, has_archive=True)
-        outguess_dir = output_dir / "outguess"
+
-        outguess_dir.mkdir(parents=True, exist_ok=True)
+    def build_cmd(self, password: Optional[str] = None) -> list[str]:
-        outguess_file = "outguess.data"
+        extracted_dir = self.get_extracted_dir()
-        stderr = ""
+        assert extracted_dir is not None  # since has_archive is True
-        cmd: list[str]
+        out = str(extracted_dir / "outguess.data")
         if password:
-            cmd = [
+            return ["outguess", "-k", password, "-r", self.img, out]
-                "outguess",
-                "-k",
-                password,
-                "-r",
-                "../../" + str(image_name),
-                outguess_file,
-            ]
         else:
-            cmd = ["outguess", "-r", "../../" + str(image_name), outguess_file]
+            return ["outguess", "-r", self.img, out]
 
-        data = subprocess.run(
-            cmd,
-            cwd=outguess_dir,
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
 
-        if data.returncode != 0:
+def analyze_outguess(input_img: Path, output_dir: Path, password: Optional[str] = None) -> None:
-            stderr += data.stderr
+    """Analyze an image submission using outguess."""
-            err = {
+    analyzer = OutguessAnalyzer(input_img, output_dir)
-                "outguess": {
+    if password:
-                    "status": "error",
+        analyzer.analyze(password)
-                    "error": stderr,
+    else:
-                }
+        analyzer.analyze()
-            }
-            update_data(output_dir, err)
-            return None
-
-        # Zip extracted files
-        zip_data = subprocess.run(
-            ["7z", "a", "../outguess.7z", "*"],
-            cwd=outguess_dir,
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-
-        stderr += zip_data.stderr
-
-        if len(stderr) > 0:
-            err = {
-                "outguess": {
-                    "status": "error",
-                    "error": stderr,
-                }
-            }
-            update_data(output_dir, err)
-            return None
-
-        # Remove the extracted directory
-        shutil.rmtree(outguess_dir)
-
-        data_strings = data.stderr.split("\n") if data else []
-        data_strings = [s for s in data_strings if s]
-
-        update_data(
-            output_dir,
-            {
-                "outguess": {
-                    "status": "ok",
-                    "output": data_strings,
-                    "download": f"/download/{output_dir.name}/outguess",
-                }
-            },
-        )
-
-    except Exception as e:
-        update_data(output_dir, {"outguess": {"status": "error", "error": str(e)}})
-    return None

aperisolve/analyzers/pngcheck.py

@@ -3,54 +3,23 @@
 # mypy: disable-error-code=unused-awaitable
 """Pngcheck Analyzer for Image Submissions."""
 
-import subprocess
 from pathlib import Path
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class PngcheckAnalyzer(SubprocessAnalyzer):
+    """Analyzer for pngcheck."""
+
+    def __init__(self, *args):
+        super().__init__("pngcheck", *args)
+        self.cmd = ["pngcheck", "-v", self.img]
+
+    def is_error(self, returncode: int, stdout: str, stderr: str, zip_exist: bool) -> bool:
+        return "this is neither a PNG or JNG image nor a MNG stream" in stdout
 
 
 def analyze_pngcheck(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using pngcheck."""
-
+    analyzer = PngcheckAnalyzer(input_img, output_dir)
-    try:
+    analyzer.analyze()
-        data = subprocess.run(
-            ["pngcheck", "-v", input_img],
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        # Error based on https://github.com/pnggroup/pngcheck/issues/59
-        # if data.stderr:
-        #     update_data(
-        #         output_dir, {"pngcheck": {"status": "error", "error": data.stderr}}
-        #     )
-        #     return
-
-        if "this is neither a PNG or JNG image nor a MNG stream" in data.stdout:
-            update_data(
-                output_dir,
-                {
-                    "pngcheck": {
-                        "status": "error",
-                        "error": "ERRORS DETECTED: this is neither a PNG or JNG image nor a "
-                        "MNG stream.",
-                    }
-                },
-            )
-            return
-
-        data_pngcheck = data.stdout.split("\n") if data else []
-        data_pngcheck = [s for s in data_pngcheck if s]
-
-        update_data(
-            output_dir,
-            {
-                "pngcheck": {
-                    "status": "ok",
-                    "output": data_pngcheck,
-                }
-            },
-        )
-    except Exception as e:
-        update_data(output_dir, {"pngcheck": {"status": "error", "error": str(e)}})

aperisolve/analyzers/steghide.py

@@ -4,127 +4,67 @@
 """Steghide Analyzer for Image Submissions."""
 
 import re
-import shutil
-import subprocess
 from pathlib import Path
 from typing import Optional
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
 
 
-def analyze_steghide(
+class SteghideAnalyzer(SubprocessAnalyzer):
-    input_img: Path, output_dir: Path, password: Optional[str] = None
+    """Analyzer for steghide."""
-) -> None:
-    """Analyze an image submission using steghide."""
 
-    image_name = input_img.name
+    def __init__(self, *args):
-    try:
+        super().__init__("steghide", *args, has_archive=True)
-        stderr = ""
-        # Get embedded file information first
-        cmd: list[str] = ["steghide", "info", "../" + str(image_name)]
-        if password:
-            cmd += ["-p", password]
-        else:
-            cmd += ["-p", ""]
 
-        data = subprocess.run(
+    def build_cmd(self, password: Optional[str] = None) -> list[str]:
-            cmd,
+        if password is None:
-            cwd=output_dir,
+            password = ""
-            capture_output=True,
+
-            text=True,
+        # First, get the embedded file name, and return the test cmd if failed
-            check=False,
+        cmd_test = ["steghide", "info", self.img, "-p", password]
-            timeout=MAX_PENDING_TIME,
+        data = self.run_command(cmd_test, cwd=self.output_dir)
-        )
+        err = self.is_error(data.returncode, data.stdout, data.stderr, False)
+        if err:
+            return cmd_test
 
         match = re.search(r'embedded file "([^"]+)"', data.stdout)
+        assert match is not None
+        hidden = match.group(1)
+        cmd = ["steghide", "extract", "-sf", self.img, "-xf", hidden, "-p", password]
+        return cmd
+
+    def is_error(self, returncode: int, stdout: str, stderr: str, zip_exist: bool) -> bool:
+        """Check if the result is an error."""
+
+        match = re.search(r'embedded file "([^"]+)"', stdout)
         embedded_filename = match.group(1) if match else None
 
         # if bad file format or wrong password, raise an error
-        if data.returncode != 0 or embedded_filename is None:
+        return returncode != 0 or embedded_filename is None
-            stderr += data.stderr.replace(f'"../{image_name}" ', "")  # hide file name
-            # the file format of the file \"../foobar.png\"  is not supported.
-            # become
-            # the file format of the file is not supported.
-            err = {
-                "steghide": {
-                    "status": "error",
-                    "error": stderr,
-                }
-            }
-            update_data(output_dir, err)
-            return None
 
-        # The passphrase is correct, we can extract the file
+    def process_output(self, stdout: str, stderr: str) -> str | list[str] | dict[str, str]:
-        # prevent path traversal
+        """Process the stdout into a list of lines."""
-        embedded_file = output_dir / "steghide" / str(Path(embedded_filename).name)
+        out = []
-        extracted_dir = embedded_file.parent
+        for line in stderr.split("\n"):
-        extracted_dir.mkdir(parents=True, exist_ok=True)
-
-        cmd_ext: list[str] = [
-            "steghide",
-            "extract",
-            "-sf",
-            "../../" + str(image_name),
-            "-xf",
-            str(embedded_file.name),
-        ]
-        if password:
-            cmd_ext += ["-p", password]
-        else:
-            cmd_ext += ["-p", ""]
-
-        data = subprocess.run(
-            cmd_ext,
-            cwd=extracted_dir,
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        # Filter out lines that indicate success
-        stdout = []
-        for line in data.stderr.split("\n"):
             if line.startswith('wrote extracted data to "'):
-                stdout.append(line)
+                out.append(line)
-            elif line:
+        return out
-                stderr += line + "\n"
 
-        # Zip extracted files
+    def process_error(self, stdout: str, stderr: str) -> str:
-        zip_data = subprocess.run(
+        """Process stderr."""
-            ["7z", "a", "../steghide.7z", "*"],
+        if "the file format of the file" in stderr and "not supported" in stderr:
-            cwd=extracted_dir,
+            return "The file format of the file is not supported (JPEG or BMP only)."
-            capture_output=True,
+        out = ""
-            text=True,
+        for line in stderr.split("\n"):
-            check=False,
+            if line and not line.startswith('wrote extracted data to "'):
-            timeout=MAX_PENDING_TIME,
+                out += line + "\n"
-        )
+        return out
 
-        stderr += zip_data.stderr
 
-        if len(stderr) > 0:
+def analyze_steghide(input_img: Path, output_dir: Path, password: Optional[str] = None) -> None:
-            err = {
+    """Analyze an image submission using steghide."""
-                "steghide": {
+    analyzer = SteghideAnalyzer(input_img, output_dir)
-                    "status": "error",
+    if password:
-                    "error": stderr,
+        analyzer.analyze(password)
-                }
+    else:
-            }
+        analyzer.analyze()
-            update_data(output_dir, err)
-            return None
-
-        # Remove the extracted directory
-        shutil.rmtree(extracted_dir)
-
-        update_data(
-            output_dir,
-            {
-                "steghide": {
-                    "status": "ok",
-                    "output": stdout,
-                    "download": f"/download/{output_dir.name}/steghide",
-                }
-            },
-        )
-
-    except Exception as e:
-        update_data(output_dir, {"steghide": {"status": "error", "error": str(e)}})
-    return None

aperisolve/analyzers/strings.py

@@ -3,45 +3,20 @@
 # mypy: disable-error-code=unused-awaitable
 """Strings Analyzer for Image Submissions."""
 
-import subprocess
 from pathlib import Path
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class StringsAnalyzer(SubprocessAnalyzer):
+    """Analyzer for strings."""
+
+    def __init__(self, *args):
+        super().__init__("strings", *args)
+        self.cmd = ["strings", self.img]
 
 
 def analyze_strings(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using strings."""
-
+    analyzer = StringsAnalyzer(input_img, output_dir)
-    try:
+    analyzer.analyze()
-        data = subprocess.run(
-            ["strings", input_img],
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        if data.stderr:
-            update_data(
-                output_dir, {"strings": {"status": "error", "error": data.stderr}}
-            )
-            return
-
-        # strings_dir = output_dir / "strings"
-        # strings_dir.mkdir(parents=True, exist_ok=True)
-        # with open(strings_dir / "strings.txt", "w", encoding="utf-8") as f:
-        #    subprocess.run(["strings", input_img], stdout=f, check=True)
-
-        data_strings = data.stdout.split("\n") if data else []
-        data_strings = [s for s in data_strings if s]
-
-        update_data(
-            output_dir,
-            {
-                "strings": {
-                    "status": "ok",
-                    "output": data_strings,
-                }
-            },
-        )
-    except Exception as e:
-        update_data(output_dir, {"strings": {"status": "error", "error": str(e)}})

aperisolve/analyzers/template_analyzer.py

@@ -1,79 +1,30 @@
 # flake8: noqa: E203,E501,W503
 # pylint: disable=C0413,W0718,R0903,R0801
 # mypy: disable-error-code=unused-awaitable
-"""Custom Analyzer for Image Submissions."""
+"""<toolname> Analyzer for Image Submissions."""
 
-import shutil
-import subprocess
 from pathlib import Path
+from typing import Optional
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
 
 
-def analyze_myanalyzer(input_img: Path, output_dir: Path) -> None:
+class TemplateAnalyze(SubprocessAnalyzer):
-    """Analyze an image submission using myanalyzer."""
+    """Analyzer for <toolname>."""
 
-    image_name = input_img.name
+    def __init__(self, *args):
+        super().__init__("<toolname>", *args, has_archive=True)
 
-    # Dir generated by the tool
+    def build_cmd(self, password: Optional[str] = None) -> list[str]:
-    extracted_dir = output_dir / "myanalyzer_output_dir"
+        if password:
+            return ["<toolname>", "-p", password, "-i", self.img]
+        return ["<toolname>", "-i", self.img]
 
-    try:
-        stderr, stdout = "", ""
 
-        # Run myanalyzer
+def analyze_template(input_img: Path, output_dir: Path, password: Optional[str] = None) -> None:
-        data = subprocess.run(
+    """Analyze an image submission using <toolname>."""
-            ["myanalyzer", "-e", "../" + str(image_name)],
+    analyzer = TemplateAnalyze(input_img, output_dir)
-            cwd=output_dir,
+    if password:
-            capture_output=True,
+        analyzer.analyze(password)
-            text=True,
+    else:
-            check=False,
+        analyzer.analyze()
-            timeout=MAX_PENDING_TIME,
-        )
-
-        stderr += data.stderr
-        stdout += data.stdout
-
-        if len(stderr) > 0:  # Return error if error has been raised
-            err = {
-                "myanalyzer": {
-                    "status": "error",
-                    "error": stderr,
-                }
-            }
-            update_data(output_dir, err)
-            return None
-
-        zip_exist = False
-        if extracted_dir.exists():  # If result file(s) exist, zip them
-            subprocess.run(
-                ["7z", "a", "../myanalyzer.7z", "*"],
-                cwd=extracted_dir,
-                capture_output=True,
-                text=True,
-                check=False,
-                timeout=MAX_PENDING_TIME,
-            )
-            zip_exist = True
-
-        if extracted_dir.exists():  # Remove the extracted directory
-            shutil.rmtree(extracted_dir)
-
-        output = data.stdout.split("\n") if data else []
-        output_data = {
-            "myanalyzer": {
-                "status": "ok",
-                "output": output,
-            }
-        }
-
-        if zip_exist:
-            output_data["myanalyzer"][
-                "download"
-            ] = f"/download/{output_dir.name}/myanalyzer"
-
-        update_data(output_dir, output_data)
-
-    except Exception as e:
-        update_data(output_dir, {"myanalyzer": {"status": "error", "error": str(e)}})
-    return None

aperisolve/analyzers/zsteg.py

@@ -1,43 +1,31 @@
 # flake8: noqa: E203,E501,W503
 # pylint: disable=C0413,W0718,R0903,R0801
 # mypy: disable-error-code=unused-awaitable
-"""Zsteg Analyzer for Image Submissions."""
+"""Strings Analyzer for Image Submissions."""
 
-import subprocess
 from pathlib import Path
 
-from .utils import MAX_PENDING_TIME, update_data
+from .base_analyzer import SubprocessAnalyzer
+
+
+class ZstegAnalyzer(SubprocessAnalyzer):
+    """Analyzer for zsteg."""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__("zsteg", *args, **kwargs)
+        self.cmd = ["zsteg", self.img]
+
+    def is_error(self, returncode: int, stdout: str, stderr: str, zip_exist: bool) -> bool:
+        return bool(stderr) or "PNG::NotSupported" in stdout[:100]
+
+    def process_error(self, stdout: str, stderr: str) -> str:
+        """Process the stderr."""
+        if "PNG::NotSupported" in stdout[:100]:
+            return "The file format of the file is not supported (PNG only)."
+        return stderr
 
 
 def analyze_zsteg(input_img: Path, output_dir: Path) -> None:
     """Analyze an image submission using zsteg."""
-
+    analyzer = ZstegAnalyzer(input_img, output_dir)
-    try:
+    analyzer.analyze()
-        data = subprocess.run(
-            ["zsteg", input_img],
-            capture_output=True,
-            text=True,
-            check=False,
-            timeout=MAX_PENDING_TIME,
-        )
-        if data.stderr or "PNG::NotSupported" in data.stdout[:100]:
-            error_msg = data.stderr or data.stdout
-            update_data(output_dir, {"zsteg": {"status": "error", "error": error_msg}})
-            return
-
-        # zsteg_dir = output_dir / "zsteg"
-        # zsteg_dir.mkdir(parents=True, exist_ok=True)
-        # with open(zsteg_dir / "zsteg.txt", "w", encoding="utf-8") as f:
-        #     subprocess.run(["zsteg", input_img], stdout=f, check=True)
-
-        update_data(
-            output_dir,
-            {
-                "zsteg": {
-                    "status": "ok",
-                    "output": data.stdout.split("\n") if data else [],
-                }
-            },
-        )
-    except Exception as e:
-        update_data(output_dir, {"zsteg": {"status": "error", "error": str(e)}})