CVE-2020-5523

Android App 'MyPallete' and some of the Android banking applications based on 'MyPallete' do not verify X.509 certificates from servers, and also do not properly validate certificates with host-mismatch, which allows man-in-the-middle attackers to spoof servers and obtain sensitive information via a crafted certificate.

Published: 2020-01-28 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-5523 is rated Moderate Risk (50.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.45%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-5523

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-03-30 0.50% 0.45% -0.05%
2 2025-03-29 0.45% 0.50% +0.05%
3 2025-03-17 — 0.45% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-5523

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2020-5523

Affected software / configurations for CVE-2020-5523

Vendor Product Version Raw CPE
77bank 77_bank <= 2.0.1 cpe:2.3:a:77bank:77_bank:*:*:*:*:*:android:*:*
ashikagabank ashigin <= 1.0.4 cpe:2.3:a:ashikagabank:ashigin:*:*:*:*:*:android:*:*
hokkaidobank dogin <= 3.0.1 cpe:2.3:a:hokkaidobank:dogin:*:*:*:*:*:android:*:*
hokugin hokuriku_bank_portal <= 2.0.1 cpe:2.3:a:hokugin:hokuriku_bank_portal:*:*:*:*:*:android:*:*
naganobank nagagin <= 1.0.1 cpe:2.3:a:naganobank:nagagin:*:*:*:*:*:android:*:*
nttdata mypallete — cpe:2.3:a:nttdata:mypallete:-:*:*:*:*:android:*:*
shikokubank shikoku_bank <= 2.0.1 cpe:2.3:a:shikokubank:shikoku_bank:*:*:*:*:*:android:*:*
sihd-bk ikeda_senshu_bank <= 3.0.4 cpe:2.3:a:sihd-bk:ikeda_senshu_bank:*:*:*:*:*:android:*:*
tohoku-bank tougin <= 1.0.1 cpe:2.3:a:tohoku-bank:tougin:*:*:*:*:*:android:*:*

References for CVE-2020-5523

URL Tags
http://jvn.jp/en/jp/JVN28845872/index.html Third Party Advisory
http://www.dokodemobank.ne.jp/info_20200128_bankingapp.html Third Party Advisory
https://www.77bank.co.jp/pdf/oshirase/20012801_appvulnerability.pdf Third Party Advisory
https://www.ashikagabank.co.jp/appbanking/pdf/oshirase.pdf Third Party Advisory
https://www.hokkaidobank.co.jp/common/dat/2020/0120/15795047141946146699.pdf Third Party Advisory
https://www.hokugin.co.jp/info/archives/personal/2020/1913.html Third Party Advisory
https://www.naganobank.co.jp/soshiki/2/app-ssl.html Third Party Advisory
https://www.shikokubank.co.jp/info/apps20200128.html Third Party Advisory
https://www.sihd-bk.jp/common_v2/pdf/20200127.pdf Third Party Advisory
https://www.tohoku-bank.co.jp/news/topics/200128_applissl.html Third Party Advisory
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