[EFR][HOTFIX] QA Request (#2306)

* Scan independent library file (.so, .dylib, Framework dylib) from APK/IPA Static Analysis Report
* Library analysis refactored relative path helper for Django template.
* Re-introduced RELRO checks for Android, added Dart binary check to avoid Flutter false positives.
* Improved stripped debug symbol check for ELF and MachO using native OS tools such as nm and objdump when available.
* Merge iOS Framework and Dylib Analysis.

mobsf/MobSF/init.py

@@ -10,7 +10,7 @@
 
 logger = logging.getLogger(__name__)
 
-VERSION = '3.8.6'
+VERSION = '3.8.7'
 BANNER = """
   __  __       _    ____  _____       _____  ___  
  |  \/  | ___ | |__/ ___||  ___|_   _|___ / ( _ ) 

mobsf/MobSF/urls.py

@@ -149,7 +149,10 @@
         # App Compare
         re_path(r'^compare/(?P<hash1>[0-9a-f]{32})/(?P<hash2>[0-9a-f]{32})/$',
                 shared_func.compare_apps),
-
+        # Relative Shared & Dynamic Library scan
+        re_path(r'^scan_library/(?P<checksum>[0-9a-f]{32})$',
+                shared_func.scan_library,
+                name='scan_library'),
         # Dynamic Analysis
         re_path(r'^android/dynamic_analysis/$',
                 dz.android_dynamic_analysis,

mobsf/MobSF/utils.py

@@ -19,6 +19,7 @@
 import sqlite3
 import unicodedata
 import threading
+from pathlib import Path
 from distutils.version import StrictVersion
 
 import distro
@@ -491,6 +492,8 @@ def update_local_db(db_name, url, local_file):
         else:
             logger.info('%s Database is up-to-date', db_name)
         return update
+    except requests.exceptions.ReadTimeout:
+        logger.warning('Failed to download %s DB.', db_name)
     except Exception:
         logger.exception('[ERROR] %s DB Update', db_name)
         return update
@@ -758,6 +761,21 @@ def replace(value, arg):
     return value.replace(what, to)
 
 
+def relative_path(value):
+    """Show relative path to two parents."""
+    sep = None
+    if '/' in value:
+        sep = '/'
+    elif '\\\\' in value:
+        sep = '\\\\'
+    elif '\\' in value:
+        sep = '\\'
+    if not sep or value.count(sep) < 2:
+        return value
+    path = Path(value)
+    return path.relative_to(path.parent.parent).as_posix()
+
+
 def pretty_json(value):
     """Pretty print JSON."""
     try:

mobsf/StaticAnalyzer/views/android/jar_aar.py

@@ -142,7 +142,10 @@ def common_analysis(request, app_dic, rescan, api, analysis_type):
                 'certificate_summary': {},
             }
         app_dic['real_name'] = ''
-        elf_dict = library_analysis(app_dic['app_dir'], 'elf')
+        elf_dict = library_analysis(
+            app_dic['app_dir'],
+            app_dic['md5'],
+            'elf')
         tracker = Trackers.Trackers(
             app_dic['app_dir'],
             app_dic['tools_dir'])

mobsf/StaticAnalyzer/views/android/so.py

@@ -88,7 +88,10 @@ def so_analysis(request, app_dic, rescan, api):
             'certificate_summary': {},
         }
         app_dic['real_name'] = ''
-        elf_dict = library_analysis(app_dic['app_dir'], 'elf')
+        elf_dict = library_analysis(
+            app_dic['app_dir'],
+            app_dic['md5'],
+            'elf')
         # File Analysis is used to store symbols from so
         app_dic['certz'] = get_symbols(
             elf_dict['elf_symbols'])

mobsf/StaticAnalyzer/views/android/static_analyzer.py

@@ -25,6 +25,7 @@
     is_md5,
     key,
     print_n_send_error_response,
+    relative_path,
 )
 from mobsf.StaticAnalyzer.models import (
     RecentScansDB,
@@ -92,6 +93,7 @@
 
 register.filter('key', key)
 register.filter('android_component', android_component)
+register.filter('relative_path', relative_path)
 
 
 def static_analyzer(request, checksum, api=False):
@@ -211,7 +213,10 @@ def static_analyzer(request, checksum, api=False):
                 # apktool should run before this
                 get_icon_apk(apk, app_dic)
 
-                elf_dict = library_analysis(app_dic['app_dir'], 'elf')
+                elf_dict = library_analysis(
+                    app_dic['app_dir'],
+                    app_dic['md5'],
+                    'elf')
                 cert_dic = cert_info(
                     apk,
                     app_dic,

mobsf/StaticAnalyzer/views/common/a.py

@@ -116,7 +116,10 @@ def a_analysis(request, app_dict, rescan, api):
             'framework_analysis': {},
         }
         # Analyze static library
-        slib = library_analysis(app_dict['bin_dir'], 'ar')
+        slib = library_analysis(
+            app_dict['bin_dir'],
+            app_dict['md5_hash'],
+            'ar')
         bin_dict['bin_info']['arch'] = slib['ar_a']
         bin_dict['dylib_analysis'] = slib['ar_analysis']
         # Store Symbols in File Analysis

mobsf/StaticAnalyzer/views/common/binary/elf.py

@@ -1,12 +1,33 @@
 # !/usr/bin/python
 # coding=utf-8
+import shutil
+import subprocess
+
 import lief
 
 from mobsf.StaticAnalyzer.views.common.binary.strings import (
     strings_on_binary,
 )
 
 
+NA = 'Not Applicable'
+NO_RELRO = 'No RELRO'
+PARTIAL_RELRO = 'Partial RELRO'
+FULL_RELRO = 'Full RELRO'
+INFO = 'info'
+WARNING = 'warning'
+HIGH = 'high'
+
+
+def nm_is_debug_symbol_stripped(elf_file):
+    """Check if debug symbols are stripped using OS utility."""
+    # https://linux.die.net/man/1/nm
+    out = subprocess.check_output(
+        [shutil.which('nm'), '--debug-syms', elf_file],
+        stderr=subprocess.STDOUT)
+    return b'no debug symbols' in out
+
+
 class ELFChecksec:
     def __init__(self, elf_file, so_rel):
         self.elf_path = elf_file.as_posix()
@@ -20,13 +41,13 @@ def checksec(self):
             return
         is_nx = self.is_nx()
         if is_nx:
-            severity = 'info'
+            severity = INFO
             desc = (
                 'The binary has NX bit set. This marks a '
                 'memory page non-executable making attacker '
                 'injected shellcode non-executable.')
         else:
-            severity = 'high'
+            severity = HIGH
             desc = (
                 'The binary does not have NX bit set. NX bit '
                 'offer protection against exploitation of memory corruption '
@@ -40,15 +61,15 @@ def checksec(self):
         }
         has_canary = self.has_canary()
         if has_canary:
-            severity = 'info'
+            severity = INFO
             desc = (
                 'This binary has a stack canary value '
                 'added to the stack so that it will be overwritten by '
                 'a stack buffer that overflows the return address. '
                 'This allows detection of overflows by verifying the '
                 'integrity of the canary before function return.')
         else:
-            severity = 'high'
+            severity = HIGH
             desc = (
                 'This binary does not have a stack '
                 'canary value added to the stack. Stack canaries '
@@ -62,9 +83,47 @@ def checksec(self):
             'severity': severity,
             'description': desc,
         }
+        relro = self.relro()
+        if relro == NA:
+            severity = INFO
+            desc = ('RELRO checks are not applicable for '
+                    'Flutter/Dart binaries')
+        elif relro == FULL_RELRO:
+            severity = INFO
+            desc = (
+                'This shared object has full RELRO '
+                'enabled. RELRO ensures that the GOT cannot be '
+                'overwritten in vulnerable ELF binaries. '
+                'In Full RELRO, the entire GOT (.got and '
+                '.got.plt both) is marked as read-only.')
+        elif relro == PARTIAL_RELRO:
+            severity = WARNING
+            desc = (
+                'This shared object has partial RELRO '
+                'enabled. RELRO ensures that the GOT cannot be '
+                'overwritten in vulnerable ELF binaries. '
+                'In partial RELRO, the non-PLT part of the GOT '
+                'section is read only but .got.plt is still '
+                'writeable. Use the option -z,relro,-z,now to '
+                'enable full RELRO.')
+        else:
+            severity = HIGH
+            desc = (
+                'This shared object does not have RELRO '
+                'enabled. The entire GOT (.got and '
+                '.got.plt both) are writable. Without this compiler '
+                'flag, buffer overflows on a global variable can '
+                'overwrite GOT entries. Use the option '
+                '-z,relro,-z,now to enable full RELRO and only '
+                '-z,relro to enable partial RELRO.')
+        elf_dict['relocation_readonly'] = {
+            'relro': relro,
+            'severity': severity,
+            'description': desc,
+        }
         rpath = self.rpath()
         if rpath:
-            severity = 'high'
+            severity = HIGH
             desc = (
                 'The binary has RPATH set. In certain cases, '
                 'an attacker can abuse this feature to run arbitrary '
@@ -75,7 +134,7 @@ def checksec(self):
                 'compiler option -rpath to remove RPATH.')
             rpt = rpath.rpath
         else:
-            severity = 'info'
+            severity = INFO
             desc = (
                 'The binary does not have run-time search path '
                 'or RPATH set.')
@@ -87,7 +146,7 @@ def checksec(self):
         }
         runpath = self.runpath()
         if runpath:
-            severity = 'high'
+            severity = HIGH
             desc = (
                 'The binary has RUNPATH set. In certain cases, '
                 'an attacker can abuse this feature and or modify '
@@ -99,7 +158,7 @@ def checksec(self):
                 'option --enable-new-dtags,-rpath to remove RUNPATH.')
             rnp = runpath.runpath
         else:
-            severity = 'info'
+            severity = INFO
             desc = (
                 'The binary does not have RUNPATH set.')
             rnp = runpath
@@ -110,14 +169,14 @@ def checksec(self):
         }
         fortified_functions = self.fortify()
         if fortified_functions:
-            severity = 'info'
+            severity = INFO
             desc = ('The binary has the '
                     f'following fortified functions: {fortified_functions}')
         else:
             if self.is_dart():
-                severity = 'info'
+                severity = INFO
             else:
-                severity = 'warning'
+                severity = WARNING
             desc = ('The binary does not have any '
                     'fortified functions. Fortified functions '
                     'provides buffer overflow checks against '
@@ -133,10 +192,10 @@ def checksec(self):
         }
         is_stripped = self.is_symbols_stripped()
         if is_stripped:
-            severity = 'info'
+            severity = INFO
             desc = 'Symbols are stripped.'
         else:
-            severity = 'warning'
+            severity = WARNING
             desc = 'Symbols are available.'
         elf_dict['symbol'] = {
             'is_stripped': is_stripped,
@@ -176,6 +235,34 @@ def has_canary(self):
                 pass
         return False
 
+    def relro(self):
+        try:
+            gnu_relro = lief.ELF.SEGMENT_TYPES.GNU_RELRO
+            bind_now_flag = lief.ELF.DYNAMIC_FLAGS.BIND_NOW
+            flags_tag = lief.ELF.DYNAMIC_TAGS.FLAGS
+            flags1_tag = lief.ELF.DYNAMIC_TAGS.FLAGS_1
+            now_flag = lief.ELF.DYNAMIC_FLAGS_1.NOW
+
+            if self.is_dart():
+                return NA
+
+            if not self.elf.get(gnu_relro):
+                return NO_RELRO
+
+            flags = self.elf.get(flags_tag)
+            bind_now = flags and bind_now_flag in flags
+
+            flags1 = self.elf.get(flags1_tag)
+            now = flags1 and now_flag in flags1
+
+            if bind_now or now:
+                return FULL_RELRO
+            else:
+                return PARTIAL_RELRO
+        except lief.not_found:
+            pass
+        return NO_RELRO
+
     def rpath(self):
         try:
             rpath = lief.ELF.DYNAMIC_TAGS.RPATH
@@ -191,10 +278,14 @@ def runpath(self):
             return False
 
     def is_symbols_stripped(self):
-        for i in self.elf.static_symbols:
-            if i:
-                return False
-        return True
+        try:
+            return nm_is_debug_symbol_stripped(
+                self.elf_path)
+        except Exception:
+            for i in self.elf.static_symbols:
+                if i:
+                    return False
+            return True
 
     def fortify(self):
         fortified_funcs = []