Published:2020/03/24  Last Updated:2020/03/24

Keijiban Tsumiki vulenrable to OS command injection


Keijiban Tsumiki contains an OS command injection vulnerability.

Vendor Information

Mash room - Free CGI -

Keijiban Tsumiki v1.15


Keijiban Tsumiki provided by Mash room - Free CGI - is a CGI to provide Bulletin Board System (BBS) functions.
Keijiban Tsumiki contains an OS command injection vulnerability (CWE-78).


A remote attacker may execute an arbitrary OS command.


Consider stop using Keijiban Tsumiki v1.15
Since the developer was unreachable, existence of any mitigations is unknown.

Vendor Opinion

None provided

JPCERT/CC Addendum

During the meeting of Committee for authorizing the disclosure of unresolved vulnerabilities held on January 16, 2020, 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 Other 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 6 separate emails (sent from February 20 to September 24, 2019)
    - No response to disclosure of the developer's name (listed on June 22, 2012) in "List of unreachable developers" and to the disclosure of the name and its version (listed on September 27, 2012) in “Information Resuest” on JVN
    - No response to the announcement of screening procedure for vulnerability disclosure (sent on December 18, 2019)

  2. Existence of vulnerability has been verified:
    It was verified that the product contains an OS command injection vulnerability by IPA.  Since an arbitrary OS command can be executed on the server, this violates the "Confidentiality" 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 directory traversal vulnerability.  It was determined that disclosure of this vulnerability is legitimate under these condition.

  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: 7.3
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: 7.5
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
・October 16, 2019

Validation environment (Server, Product version 1.02)
・CentOS Linux 7.6.1810
・Apache 2.4.16
・PHP 5.4.16
Bulletin Board System Tsumiki v1.02

Validation environment (Client)
・Microsoft Windows 10 Pro (64-bit) 1903/18362.418
・Microsoft Internet Explorer11 11.0.155

Validation result
・An OS command was executed on the server running the product
 (Bulletin Board System Tsumiki v1.0)


Other Information

JPCERT Reports
CERT Advisory
CPNI Advisory
CVE CVE-2020-5561
JVN iPedia JVNDB-2020-000908