CVE-2017-9855 [Critical] | Security Vulnerability in Sunny Boy 3600 Firmware

An issue was discovered in SMA Solar Technology products. A secondary authentication system is available for Installers called the Grid Guard system. This system uses predictable codes, and a single Grid Guard code can be used on any SMA inverter. Any such code, when combined with the installer account, allows changing very sensitive parameters. NOTE: the vendor reports that Grid Guard is not an authentication feature; it is only a tracing feature. Also, 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	0.78%	0.44%	-0.34%
2	2025-03-29	0.44%	0.78%	+0.34%
3	2025-03-17	—	0.44%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2025-03-30

0.78%

0.44%

-0.34%

2025-03-29

0.44%

0.78%

+0.34%

2025-03-17

—

0.44%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.1	CRITICAL	`CVSS:3.1/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	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]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/A:P` 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:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.1

CRITICAL

CVSS:3.1/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

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]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P 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:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

Affected software / configurations for CVE-2017-9855

References for CVE-2017-9855

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-2017-9855

Exploit prediction scoring system (EPSS) score for CVE-2017-9855

Common vulnerability scoring system (CVSS) metrics for CVE-2017-9855

Weakness enumeration for CVE-2017-9855

Affected software / configurations for CVE-2017-9855

References for CVE-2017-9855

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:-:::::::*