CVE-2017-9856 [Low] | Security Vulnerability in Sunny Boy 3600 Firmware

An issue was discovered in SMA Solar Technology products. Sniffed passwords from SMAdata2+ communication can be decrypted very easily. The passwords are "encrypted" using a very simple encryption algorithm. This enables an attacker to find the plaintext passwords and authenticate to the device. NOTE: the vendor reports that only Sunny Boy TLST-21 and TL-21 and Sunny Tripower TL-10 and TL-30 could potentially be affected

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2025-03-30	0.34%	0.18%	-0.17%
2	2025-03-29	0.24%	0.34%	+0.10%
3	2023-03-07	—	0.24%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-03-30

0.34%

0.18%

-0.17%

2025-03-29

0.24%

0.34%

+0.10%

2023-03-07

—

0.24%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
3.4	3.1	LOW	`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	1.6	1.4	134c704f-9b21-4f2e-91b3-4a467353bcc0
9.8	3.0	CRITICAL	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` 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:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. 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:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:P/I:N/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:N) No availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

3.4

3.1

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:N/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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

1.6

1.4

134c704f-9b21-4f2e-91b3-4a467353bcc0

9.8

3.0

CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H 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:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:N): No availability impact.

10.0

2.9

[email protected]

Affected software / configurations for CVE-2017-9856

References for CVE-2017-9856

URL	Tags
http://www.sma.de/en/statement-on-cyber-security.html
http://www.sma.de/fileadmin/content/global/specials/documents/cyber-security/Whitepaper-Cyber-Security-AEN1732_07.pdf
https://horusscenario.com/CVE-information/	Third Party Advisory

URL

CVE-2017-9856

Exploit prediction scoring system (EPSS) score for CVE-2017-9856

Common vulnerability scoring system (CVSS) metrics for CVE-2017-9856

Weakness enumeration for CVE-2017-9856

Affected software / configurations for CVE-2017-9856

References for CVE-2017-9856

Vendor	Product	Version	Raw CPE
sma	sunny_boy_3600_firmware	—	cpe:2.3:o:sma:sunny_boy_3600_firmware:-:::::::*
sma	sunny_boy_5000_firmware	—	cpe:2.3:o:sma:sunny_boy_5000_firmware:-:::::::*
sma	sunny_tripower_core1_firmware	—	cpe:2.3:o:sma:sunny_tripower_core1_firmware:-:::::::*
sma	sunny_tripower_15000tl_firmware	—	cpe:2.3:o:sma:sunny_tripower_15000tl_firmware:-:::::::*
sma	sunny_tripower_20000tl_firmware	—	cpe:2.3:o:sma:sunny_tripower_20000tl_firmware:-:::::::*
sma	sunny_tripower_25000tl_firmware	—	cpe:2.3:o:sma:sunny_tripower_25000tl_firmware:-:::::::*
sma	sunny_tripower_5000tl_firmware	—	cpe:2.3:o:sma:sunny_tripower_5000tl_firmware:-:::::::*
sma	sunny_tripower_12000tl_firmware	—	cpe:2.3:o:sma:sunny_tripower_12000tl_firmware:-:::::::*
sma	sunny_tripower_60_firmware	—	cpe:2.3:o:sma:sunny_tripower_60_firmware:-:::::::*
sma	sunny_boy_3000tl_firmware	—	cpe:2.3:o:sma:sunny_boy_3000tl_firmware:-:::::::*
sma	sunny_boy_3600tl_firmware	—	cpe:2.3:o:sma:sunny_boy_3600tl_firmware:-:::::::*
sma	sunny_boy_4000tl_firmware	—	cpe:2.3:o:sma:sunny_boy_4000tl_firmware:-:::::::*
sma	sunny_boy_5000tl_firmware	—	cpe:2.3:o:sma:sunny_boy_5000tl_firmware:-:::::::*
sma	sunny_boy_1.5_firmware	—	cpe:2.3:o:sma:sunny_boy_1.5_firmware:-:::::::*
sma	sunny_boy_2.5_firmware	—	cpe:2.3:o:sma:sunny_boy_2.5_firmware:-:::::::*
sma	sunny_boy_3.0_firmware	—	cpe:2.3:o:sma:sunny_boy_3.0_firmware:-:::::::*
sma	sunny_boy_3.6_firmware	—	cpe:2.3:o:sma:sunny_boy_3.6_firmware:-:::::::*
sma	sunny_boy_4.0_firmware	—	cpe:2.3:o:sma:sunny_boy_4.0_firmware:-:::::::*
sma	sunny_boy_5.0_firmware	—	cpe:2.3:o:sma:sunny_boy_5.0_firmware:-:::::::*
sma	sunny_central_2200_firmware	—	cpe:2.3:o:sma:sunny_central_2200_firmware:-:::::::*
sma	sunny_central_1000cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_1000cp_xt_firmware:-:::::::*
sma	sunny_central_800cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_800cp_xt_firmware:-:::::::*
sma	sunny_central_850cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_850cp_xt_firmware:-:::::::*
sma	sunny_central_900cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_900cp_xt_firmware:-:::::::*
sma	sunny_central_500cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_500cp_xt_firmware:-:::::::*
sma	sunny_central_630cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_630cp_xt_firmware:-:::::::*
sma	sunny_central_720cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_720cp_xt_firmware:-:::::::*
sma	sunny_central_760cp_xt_firmware	—	cpe:2.3:o:sma:sunny_central_760cp_xt_firmware:-:::::::*
sma	sunny_central_storage_500_firmware	—	cpe:2.3:o:sma:sunny_central_storage_500_firmware:-:::::::*
sma	sunny_central_storage_630_firmware	—	cpe:2.3:o:sma:sunny_central_storage_630_firmware:-:::::::*
sma	sunny_central_storage_720_firmware	—	cpe:2.3:o:sma:sunny_central_storage_720_firmware:-:::::::*
sma	sunny_central_storage_760_firmware	—	cpe:2.3:o:sma:sunny_central_storage_760_firmware:-:::::::*
sma	sunny_central_storage_800_firmware	—	cpe:2.3:o:sma:sunny_central_storage_800_firmware:-:::::::*
sma	sunny_central_storage_850_firmware	—	cpe:2.3:o:sma:sunny_central_storage_850_firmware:-:::::::*
sma	sunny_central_storage_900_firmware	—	cpe:2.3:o:sma:sunny_central_storage_900_firmware:-:::::::*
sma	sunny_central_storage_1000_firmware	—	cpe:2.3:o:sma:sunny_central_storage_1000_firmware:-:::::::*
sma	sunny_central_storage_2200_firmware	—	cpe:2.3:o:sma:sunny_central_storage_2200_firmware:-:::::::*
sma	sunny_central_storage_2500-ev_firmware	—	cpe:2.3:o:sma:sunny_central_storage_2500-ev_firmware:-:::::::*
sma	sunny_boy_storage_2.5_firmware	—	cpe:2.3:o:sma:sunny_boy_storage_2.5_firmware:-:::::::*