Published:2018/03/13  Last Updated:2018/03/13

TinyFTP Daemon vulnerable to buffer overflow


TinyFTP Daemon contains a buffer overflow vulnerability.

Vendor Information

Developer: Hisayuki Nomura

Product name and version: Tiny FTP Daemon Ver0.52d


TinyFTP Daemon provided by Hisayuki Nomura is a FTP (File Transfer Protocol) server.  TinyFTP Daemon contains a buffer overflow vulnerability (CWE-121).


An attacker may be able to cause a denial-of-service (DoS) condition or execute arbitrary code.


Consider stop using Tiny FTP Daemon Ver0.52d
Since the developer was unreachable, existence of any mitigations are unknown.

Vendor Opinion

None provided

JPCERT/CC Addendum

During the meeting of Committee for authorizing the disclosure of unresolved vulnerabilities held on December 5, 2017, it was judged that an advisory for this vulnerability  shall be disclosed since all the criteria and conditions described below which are stated in Standards for Handling Vulnerability related Information of Software Products and Others and Information Security Early Warning Partnership Guideline have been satisfied.

  1. The developer of the product is unreachable
    JPCERT/CC had tried to reach the developer for a period of time (more than 6 months) however there were no responses from the developer.  Therefore the committee reached the conclusion that it is reasonable and appropriate to judge the developer is unreachable.

    - No response to 4 separate emails (sent from May 8, 2015 to September 2, 2015)
    - No response to disclosure of the developer’s name (listed on September 18, 2015) and product name and its version (listed on December 25, 2015) in “List of unreachable developers” page on JVN.
    - No response to Announcement of screening procedure for vulnerability disclosure (sent on November 6, 2017)
  2. Existence of vulnerability has been verified
    It was verified that the product contains a code execution vulnerability by IPA.  Arbitrary code execution was confirmed which violates the "Confidentiality", "Integrity", and "Availability"of the product.  For verification details, refer to the “Verification” section.
  3. Not disclosing this case may result in the risk that product users will have no means to know of the existence of the vulnerability in the product
    By checking the developer’s website, it is assumed that users are permitted to copy, revise, or distribute the product, and it is downloadable via internet. Therefore, the developer cannot directly contact all users of this product to notify of the buffer overflow vulnerability.  It was determined that disclosure of this vulnerability is legitimate under these conditions.
  4. There are no particular reasons that would make disclosure inappropriate
    After considering the developer’s stance and the risk to product users, the committee has judged that there are no particular reasons that would make disclosure inappropriate or that disclosure may cause any other issues.

Vulnerability Analysis by JPCERT/CC

Base Score: 9.8
Attack Vector(AV) Physical (P) Local (L) Adjacent (A) Network (N)
Attack Complexity(AC) High (H) Low (L)
Privileges Required(PR) High (H) Low (L) None (N)
User Interaction(UI) Required (R) None (N)
Scope(S) Unchanged (U) Changed (C)
Confidentiality Impact(C) None (N) Low (L) High (H)
Integrity Impact(I) None (N) Low (L) High (H)
Availability Impact(A) None (N) Low (L) High (H)
Base Score: 10.0
Access Vector(AV) Local (L) Adjacent Network (A) Network (N)
Access Complexity(AC) High (H) Medium (M) Low (L)
Authentication(Au) Multiple (M) Single (S) None (N)
Confidentiality Impact(C) None (N) Partial (P) Complete (C)
Integrity Impact(I) None (N) Partial (P) Complete (C)
Availability Impact(A) None (N) Partial (P) Complete (C)


Validation Information
The vulnerability was reported to IPA and its existence was confirmed by IPA.
Date of validation
・July 24, 2017

Validation environment(Victim side)
・Microsoft Windows 7 Professional SP1 32bit Japanese version
・Microsoft Windows XP Pro version 2002 SP3 32bit Japanese version
・Tiny FTP Daemon 0.52d

Validation environment(Attacker side)
・Microsoft Windows 7 Professional SP1 32bit Japanese version
・Mozilla Firefox 53.0.1
・Python 2.7

Validation result
・The reproducibility confirmed under the environment specified below
  Microsoft Windows XP Pro version 2002 SP3 32bit Japanese version
  Microsoft Windows 7 Professional SP1 32bit Japanese version


Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
CVE CVE-2018-0541
JVN iPedia JVNDB-2018-000906