Executive Summary
- SNS Sender is a script that enables bulk SMS spamming using AWS SNS, aka Smishing, a previously unseen technique in the context of cloud attack tools.
- The script author is currently known by the alias
ARDUINO_DAS
and is prolific in the phish kit scene. - The script requires valid AWS SNS credentials compromised from an environment not subject to the SNS sandbox restrictions.
- We identified links between this actor and numerous phishing kits used to target victims’ personally identifiable information (PII) and payment card details.
- The smishing scams often take the guise of a message from the United States Postal Service (USPS) regarding a missed package delivery.
Overview
A common thread between businesses and threat actors is that both are moving workloads previously handled by traditional web servers to the cloud. SentinelLabs has identified one example of this in the form of SNS Sender, a Python script that uses AWS Simple Notification Service (SNS) to send bulk SMS messages for the purpose of spamming phishing links, aka Smishing.
SNS Sender is the first script we encountered using AWS SNS to send spam texts. The script requires access to an AWS account in which the service was already provisioned, configured, and enabled. By default, AWS accounts are subject to restrictions through a feature called the SNS sandbox. These restrictions can be removed if the customer spends $1 and provides a viable use case to AWS support, who manually review such requests. While other tools like AlienFox have used business to customer (B2C) communications platforms such as Twilio to conduct SMS spamming attacks, we are unaware of existing research that details tools abusing AWS SNS to conduct such attacks.
We identified links between the actor behind this tool and many phishing kits used to target victims’ personally identifiable information (PII) and payment card details under the guise of a message from the United States Postal Service (USPS) regarding a missed package delivery. We believe this actor is using cloud services to send bulk SMS phishing messages, though they may still be testing the tool based on some questionable programming choices.
Script Analysis
SNS Sender is a script that enables bulk SMS spamming using AWS SNS. The script requires a list of phishing links named links.txt
in its working directory. SNS Sender also takes several arguments that are entered as input:
- A text file containing a list of AWS access keys, secrets, and region delimited by a colon
- A text file containing a list of phone numbers to target
- A sender ID, similar to a display name for a message
- The message content
The send_sns_message
function sets up the AWS boto3 client–an interface between the Python script and the AWS SNS backend–to send the SMS messages. The boto3
client variables are obtained through the arguments that the script user provided.
The sender ID variable is an interesting inclusion. According to AWS documentation, this variable is optional and is supported in some countries. In the United States, carriers do not support sender IDs, whereas in India, they are mandatory. The inclusion of a sender ID contrasts with the actor’s association with USPS-themed phishing kits targeting Americans. The oversight may indicate the actor is not familiar with this exception and likely resides in a country where the sender ID is commonplace.
SNS Sender establishes a while
loop that iterates through the list of AWS credentials and regions. The script replaces any occurrences of the string linkas
in the message content variable with a URL from the links.txt
file, which weaponizes the message as a phishing SMS. The link is selected randomly using the Python random
library’s choice
method.
The script tracks how many AWS access key pairs have been accessed through the a
variable and how many phone numbers have been used through the y
variable, which are initialized as 0 and incremented by 1 each time the loop runs. Each message is sent using the credentials from one line from the AWS access key pair list, and the tracking ensures that the next line is accessed for the subsequent message.
To run at scale, the list would need to be incredibly long, and likely repeat access key & secret pairs, making this a coding method with questionable efficacy.
Phishing Kits
When investigating the handle ARDUINO_DAS
, we identified more than 150 phishing kit files containing references to the actor. More than half of the kits are USPS-themed. The assets in these archives are similar in name to the URIs present in several recent Smishing campaigns using a missed package delivery lure. We believe that the actor abandoned the ARDUINO_DAS
handle in 2023 after accusations that the actor scammed buyers. However, some recently circulated phishing kits still reference this handle, which may make it an artifact of actors using the phishing kit.
Due to the link between ARDUINO_DAS
and USPS phishing, we explored several active campaigns circulating through early January 2024, hosted on hxxps://usps[.]mytrackingh[.]top
and hxxps://u-sipsl[.]cc
. Both sites host a USPS-themed phishing site with a flow like:
- Landing Page: Explains to the visitor that their USPS package is unable to be delivered. The “Click Update” button leads to the next step.
- Tracking Page: This page looks like USPS tracking details, but it prompts the victim to enter their name, physical address, phone number, and email address.
- Card Verification Page: This page prompts the user to enter a credit card number for a $0.30 redelivery fee.
- The server forwards the details to a card checker, which is likely run through a Telegram service.
Conclusion
Actors are continuously finding new tools and platforms they can use to conduct their attack of choice, and SNS Sender is no exception. Spammers have used mega tools like AlienFox and Predator to target bulk mail services as well as business communications services. Other researchers have detailed which APIs have been used during in-the-wild AWS SNS abuse attacks, as well as enumeration routes actors may take to verify a targeted environment’s SNS capabilities. SNS Sender provides a glimpse into how actors conduct these attacks.
SNS Sender represents a more narrow approach that relies on the actor having access to a properly configured AWS SNS tenant. Using AWS presents a challenge for this actor: AWS does not allow SMS notifications via SNS by default. For this feature to work, the tenant needs to be removed from the SNS sandbox environment. This is an update from previous research where AWS automatically allowed accounts to send to 10 destination numbers while an account is in the SNS sandbox.
Organizations using AWS SNS can protect themselves by reviewing the SNS documentation for the latest information. AWS has shared guidance for organizations to learn more about the SNS sandbox and how to change sending limits. Identity and Access Management (IAM) administrators should review identity best practices to optimize their organization’s security posture.
Desire for recognition presents operational security challenges for actors developing tools for the opportunistic cloud hacking scene. The actor including their handle in the script is ubiquitous among cloud hack tools, enabling researchers to form a point of attribution even when delineating the tool families becomes challenging due to extensive overlap.
Indicators of Compromise
8fd501d7af71afee3e692a6880284616522d709e – sns_sender.py, SNS Sender
Phishing URLs
hxxps[:]//perwebsolutions[.]com/js/
hxxps[:]//usps[.]mytrackingh[.]top
hxxps[:]//u-sipsl[.]cc
Phish Kit Archives
01b82c779de9ef59ecd814d6131433f7b17d7eb0
03329461d8003aece83db2c124b5c2769dd0300e
03b0cc3f1576d0d719f5ac5dbba582a9c10e64e0
040e07a1c4cbc7eb9fb2a8ecfb865c0a2f4db5b9
04676e36b9e11f32fd675e96dd721a5a215a0641
0544db064ecb8fd8f36e96ef31d031447011c711
0547074a7cb42a67a933d70c302b626f4e10a86e
09ddd1b6f3dc1323ad86d458da05f5be605c8e7a
0a8ab120e03ed49e18ce3246b9d00f547fd9432c
0bb8a3a478d1143a04fb8abd8aa9c116282cc700
0eaa126cf4414684763b415aabc08e262ee7c194
0fb6fa2855a39f7010d3a1bcc0c08e739747785c
1024d7c1a10e94d0f926cff649a9bd9a0c5df6ba
103a49c6c4f71ab5bbcaa01df89aef80e0c90229
106b42a1a6401f6ff3cb38f66d0668ac22fbc59c
10fe02acfa1053210387bc312f1ff9529eaeba35
138a00f5e6ef81560cdfe25f2ab087c24e839efd
14ea8aa63539498773bb0d4bea5fbede05f1c17d
17a2515096e6afe5976f57887c89d3efe285ed06
1a97f72dedbdf13b13baa4c535398af25a78a28e
1b1940f128bb4f3420ebc4b5ab1a7b165e70003b
1d0a54f030e8b68bbf1256811fbb4a284ce31fda
1e85b4cf222387cddc0f2977d5c9f4a5eb03db06
1fa655639ee1f7d9c8e3157346f65d351d4b3450
1fb3a8a17123f82bf39ae93ede40273f155d5fa1
1fe0823655c30cabf51816ed1048f647172d29c8
20813f948849a05f84ed1b6a707ffc6965d17c1e
25dd30bda5bbfa7af884c0d3a71857b6abcb8222
27b6aaa536200b085d611af07b0c05df8a856eb8
29a4771a04afce2b789fe34b42a12d2fa65073ab
29d49c1d21c9e97c757db81db594e55b15587f98
2ac1467e567bc6e950b8aee96d898b71f9cf5849
2c62c5f3e4166be99bf985a0c5f08cfe5795221d
2d4f45cdfe0793431e0134376b309f1707a4e2e6
2e9bb5c725eee402a36d64f63e07f72451eaec03
319569a20fdaf2fa356f6e33e575a5a613da79b2
32a21398869e2e221552da49fe1d4beba11ad2ca
342d6e453f6a02c43ca4dee045f89cbdaa97926c
357df6a8740bca2b81b62a3a429b2fef5cc883a8
38fcec4299789a1ba16099df0842aa196c34dde6
3b15bf62091a80ec32a2c3af92da5115641cf13b
3ba42572bd49882280306fc72759016c1ea90e7c
3c6dfef72f703bd8a2779a40cef39c4eb2305e69
3d920ba992668bbb303a6680251c54c928fec988
3f31c8c8bf2acdbb3cbe792b2728b3a2eadccaec
3fc724ee8958f941168e16e06ed8f0eccffacde7
403ed75a0a86783a39e65aac0ca8d69d43f7a562
40840c0b6bd9a6a25dd864e7812cb1ee499b10bf
45a39f3af4ca67dea1f920a7bd03fe43b4b38bec
492a0031807ea7defcfb6a0be058580adac88345
4aa1f81a313c991532379f68808a59fdbecef2de
4c95a04759f5edc679122c013d2bb2570cef78dc
4cdbc5d865172d4026a624f0aa56959875ba562c
4d8bcefef73e03784fd104b8cec8bb2e3b47c89b
4f636146bc6661795a4fbde68c5ca5b48e4a462d
508d218b811aaea176b51f577a2cb74ff59ddf6e
50e6703a85b4e72834cef4438f29777c0e73af54
533ba3e5bacf6c982cc827b6aef62817897cf8ea
53c26c8f577e45ba188e18b89da4b54ff41970d0
563bc88fd217b1af0301e7eec2b03051a7236054
56d51c8d5959d33ba4c52643a6436380e4f9fd8b
589a185002c75260b66a29a21939a751d1b49585
5a61394c2b1b0da534a348ecd714810a57194574
5a6f197b77317d5d80dbe59984ccffa11cbc28ac
5aae678fdaada1e58e88fe9a8eabfddfc1fafed1
5bc0e77c722c8b973e8d2627002da3503e26dbde
5dc5dc2206059359df9bc5056dca634b8ca13004
5fe779032a8edf0866832903aac4caa4c22d65cc
60077d66f395c7af28537338bd8fed0e5f108617
601c2e36a2f284ef3bb4752b364da53afe480537
60d209585249f32d0ad24ca295911729d8f56496
64a8d7093ed1f3737901110118c768fb9ded4882
64cb6b72523df13628d2f43f400c719a556c5d86
658a6fe9f5700426d2a6b85dc035ba54b847eede
6594a9357d39e377032fc2b5094ee2f68248bffe
687f843a50e75ea74b8c51487356ee2b1ebfe359
6911cb39a03184324406f79042b648b8ed89c2d9
6c1eefaba836d8a4f86ab8cc7d9a514f045827bb
6cd850c489930ef8d2438174ab38d4c33bc70c45
6d0e9ce56f99c87d9d70e0522b96c625783aece2
7935a5760e10976d9eff013735c303069c669e72
797acd73e43b3f56961d0c687d86009fec832aee
79f93db9c9b5f42c7b26b79c926eb3dfeaee3571
7c53c7119bf6be6c5b149a1fdcb2c22b39bc1470
7c6d96174246fe907a1cb7fbe0f2592c1f8b48b7
7edcdc353071b1c44ce4a8ac33670378a86eb1ba
83e8e7da62463b79970442d2b0de2eccf36450f7
847bb302b6107ac93a669c09552ca158a1440596
87091170ae9ec6e0641d1e689a22e11324e2e4c6
87093850d8084a9a1b1881e0959acf41fcf8799c
87b41c7f499be3b765628874b37d2d0f84d53517
88dfbd8036b122a1efa32b222f985447c7c80b41
8952fbe59931daba401f615bf06b90547b6171a7
8ac6dd99742dd328b690fb6f0552f2c4df2566c6
8bc41965baba7f5e25d4bbb0519c1e4c573734c5
8f06a9204f9a354cdf4dbf4c3ae870d5a386de59
9004df92c9a9427767fdca02b9a1378cff42dbce
91065e8ab12e9fce202c0eac0290cb1bd6c46ae2
912a376b255e3b873a73767679e0fbe9a1b01446
91562cad5eb7a9568190fa4b84da4de50ed3d274
95197a29d05d2043771bc97a5ded6086f6dfbbd2
95e707b5f9257913a36fb276d25e7312a9b86156
97fba04a848da3c09bd906b6b3adb4aa9031e471
98b85e3e2bcff8b5032ddbb9758174dec2bacf58
9954725c56a9060c90b8d5cd0483fc6808f39bd1
99d35595f41a9be3fc077d37599447c096ce66cf
9a2ac6259c2707b34546bee8b5a4eec677716299
9c4593c93cc5a5d7712bee10574823ebca9f6674
9f2faa971f0f4fd783e34d11cba67b261b54cc5c
9f9fbf77fd4c3aeb1542589efdc45d4e328da56c
a19ac9df01a0bc64e636054b0a728e024ade61e9
a2163de2f5056d64a27e96a73f7858b79d47ad06
a38087ce0515cd30fb3580ba12840bc610429649
a7ec178adabbb8eb533a81c658ecce56a9e697da
ab9baecfdf85033e65d59652e666b7328cb0960d
abddb05ed3b75cae4354044bad05e5662cbfbab5
ad0d4cfcc7c35a9a96ad071a4863dbe8f83d87db
adf4765cb74c708496fa39c8c002e32b6f0c1e71
aebdd69f0bbbb8d0d3c231f0fbe1516edc5e0216
b212145149ca3f1c62e991bcf31357ecc8b17851
b2192b99736376f9e5705e81d3b55bce408e17a8
b26d632d14e91634ba01df0b3b18907657025563
b5d8b89c88f32e2c0a9166f48e87f853a497b667
b66c21bb8ef8ffa3143f3a6bae2c67f14eef069a
b6e3c52c1bd309f596b4ba50d0f7487b66bd5701
b7420fb4774e755bdb3062d12eb750687c115a3a
b7a6780990590ac3ebb632b9198b63531d645129
b841b4ae0629a5336356bce88794e0744f72f98b
ba5d94f8852f5cdee14e2bf8e1f0eb1cf599ecfb
bc0e3f1c5b323daf31ecff178c620be0c03efb64
bc3ebc37a77acef15b827e4ee43aeb839bc5605d
be0ca87b74a345d62814cad3916133e3e655acc6
bf9c85e3ed9a3f0a51eeda6284be24b507a5770f
c117393f640ccd1d5fa5b002fcc3803498b61a2d
c283818259bceaddfd62554fdf37493d413b9b84
c547caad7d7517b2026e3c17461c249a925460d3
c60830bac782f58c61a81821da8153f639c86a74
c92c68b12ba817df7eb83666bd478466cb1c423a
cabbe92c9b5acb779f9fb76b1f8e3ed77a44935d
cb27a59e95c5d1b81219ba1cae4225f7340b16f2
cc4306140f14bcec70f103f4213e96e24d065381
ce701e5c639158563455c28bc39efd2051196932
cea7151a8260b9e48b687d40a9062ad361efed2d
cf4872e3e9f580b1865f68bae6b31bca0f0e22e6
cf7f11b4a39792531118058bd1c8ba2a2cabc486
d71c9f3d3aba149d13d7434731423c164cf2f002
d77c1f97339ba891286c10f6456a1e7f44b3c3bb
d78275c82d2f10ba5ed6bfbfec37686a7646d8ea
dc7fd807e8c9fc10185dcc47bc14f7460a4228b3
dd682090d3815b52cf74b22280d1b8db02ef339e
df66269b6826273650716524219dd83cf0302dc4
df7ee28ca069f798489cb4dc2ff1295bb6377a6f
dff37819d805c0fa99f11a466f583f2f752af8b0
e2498ab48872162bab97e7a5737376cec2a5b401
e7dc9e8f82cab9de0ec3b92693cdca726c5d72a6
e95528bd91158bab9d1e998969951209f6d8a3b6
ea4c4495ac7d68543cb423d34704e8fbfd595f6b
eab2f2b4a924397d22ecd1a6e8758de585e9fdcc
ee7105ca1065b6f0f6ce4b041b1a0a95b5678790
eefcbc6b32fdf7167db0b9a455b3c8c0f8d4b58d
ef5a5d04dc048a3c1f6a415be1ad74e1478b802e
ef8b8d215b4cc107495b3957fbedd2317f642cd9
f01c586c97d68847d1f373f7fd45444af26aff7a
f28b3d223a0c351f70ec0c7680e80083c232a470
f351bd5595b1eb2196f5c2ef1c519a7a8a7967dc
f35fd34a90c7a9b827c1d9417b8f088e8302ba01
f3b5e4840139ab0465b3c432d19bae1365e923af
f5b1256e407fb37d44a54ba29dc6fd4815cfde55
f754e4a59c49c0b3e653fdd8fdc04078810524dd
fae99902bef8011459926e4a69b85ae2cf0c0914
fc9d7c59645450be5887f938aaacbca2b0b3f1f9