Arid Viper poisons Android apps with AridSpy

Key factors of the blogpost:

• ESET Analysis found three-stage Android malware, which we named AridSpy, being distributed by way of 5 devoted web sites.
• AridSpy’s code is in some circumstances bundled into functions that present respectable performance.
• Whereas the primary stage of AridSpy has been documented beforehand, right here we additionally present a full evaluation of its beforehand unknown later phases.
• AridSpy is a remotely managed trojan that focuses on consumer information espionage.
• We detected six occurrences of AridSpy, in Palestine and Egypt.
• We attribute AridSpy with medium confidence to the Arid Viper APT group.

Arid Viper, often known as APT-C-23, Desert Falcons, or Two-tailed Scorpion, is a cyberespionage group that has been lively since not less than 2013. Recognized for concentrating on nations within the Center East, the group has drawn consideration over time for its huge arsenal of malware for Android, iOS, and Home windows platforms. We reported on the group and its then-newest spy ware in a earlier blogpost.

Overview

ESET Analysis recognized 5 Arid Viper campaigns concentrating on Android customers. These campaigns delivered malware by way of devoted web sites from which victims might obtain and manually set up an Android software. Three apps supplied on these web sites are respectable apps trojanized with malicious code that we named AridSpy, whose goal is espionage. You’ll be able to see the overview scheme in Determine 1.

AridSpy was first analyzed by Zimperium in 2021; on the time, the malware solely consisted of a single stage, with all of the malicious code carried out within the trojanized software.

The second prevalence of AridSpy that ESET Analysis recognized was being utilized in 2022 (and later analyzed by 360 Beacon Labs in December 2022), the place the malware operators focused the FIFA World Cup in Qatar. Impersonating one of many many Kora functions, the marketing campaign deployed the Kora442 app bundled with AridSpy. As within the case of the pattern analyzed by Zimperium, the malware nonetheless solely had one stage presently.

In March 2023, 360 Beacon Labs analyzed one other Android marketing campaign operated by Arid Viper and located a connection between the Kora442 marketing campaign and the Arid Viper group, primarily based on use of the myScript.js file talked about in Determine 1. We discovered the identical connection within the campaigns mentioned on this blogpost (as defined within the Attribution part). It has confirmed to be a helpful indicator to determine further Arid Viper distribution web sites.

In August 2023 we logged a detection of AridSpy in our telemetry and investigated additional. We recognized targets in Palestine and Egypt. New in these campaigns, AridSpy was changed into a multistage trojan, with further payloads being downloaded from the C&C server by the preliminary, trojanized app.

On the time of this publication, three out of the 5 found campaigns are nonetheless lively; the campaigns used devoted web sites to distribute malicious apps impersonating NortirChat, LapizaChat, and ReblyChat, and the تطبيق المشغل (machine translation: Operator software; we are going to check with this because the job alternative app) and السجل المدني الفلسطيني (machine translation: Palestinian Civil Registry) apps. We found the next distribution web sites by way of our telemetry, VirusTotal, and pivoting on the shared myScript.js script utilizing the FOFA community search engine (which is an alternative choice to Shodan and Censys):

• lapizachat[.]com
• reblychat[.]com
• nortirchats[.]com
• pariberychat[.]com (inactive)
• renatchat[.]com (inactive)

Parallel to our investigation, the FOFA analysis workforce revealed a blogpost that discusses discovering seven distribution web sites with the myScript.js JavaScript file chargeable for retrieving the obtain paths for Arid Viper payloads. 4 of those web sites distributed varied variations of AridSpy. The next two had been beforehand unknown to us:

• clemochat[.]com
• voevanil[.]com

On this blogpost, we give attention to AridSpy payloads that we might receive from all of the confirmed lively distribution web sites listed above.

Notice that these malicious apps have by no means been provided by Google Play and are downloaded from third-party websites. To put in these apps, the potential sufferer is requested to allow the non-default Android choice to put in apps from unknown sources.

Victimology

Altogether we detected six occurrences of AridSpy in our telemetry, from Palestine and Egypt. The vast majority of the spy ware cases registered in Palestine had been for the malicious Palestinian Civil Registry app, with one different detection not being a part of any marketing campaign talked about on this blogpost. We then discovered the identical first-stage payload however with a distinct package deal title in Egypt. There was additionally one other first-stage payload detected in Egypt, one which makes use of the identical C&C servers because the samples within the LapizaChat and job alternative campaigns.

Attribution

We attribute AridSpy to Arid Viper with medium confidence, primarily based on these indicators:

• AridSpy focused organizations in Palestine and Egypt, which inserts a subset of Arid Viper’s typical concentrating on.
• A number of AridSpy distribution web sites use a singular, malicious JavaScript file named myScript.js, which has been beforehand linked to Arid Viper by 360 Beacon Labs and FOFA.

myScript.js was first found and linked to Arid Viper in 360 Beacon Labs’ March 30^th, 2023 evaluation of a distinct Android marketing campaign operated by Arid Viper. The (unnamed) malicious Android code utilized in that marketing campaign was beforehand attributed to the Arid Viper group. myScript.js was discovered on one of many distribution web sites used within the marketing campaign. The aim of this JavaScript code was to obtain a malicious Android app hosted on the distribution server.

Determine 2 exhibits the a part of the code that registers the handler for clicks on the web site’s Obtain button, and Determine 3 shows JavaScript code that generates file paths to obtain the malicious app.

As identified by 360 Beacon Labs, this similar JavaScript code was additionally used within the marketing campaign that focused the FIFA World Cup in Qatar with an earlier model of AridSpy, which we reported in 2022. In each campaigns, the distribution web sites used this particular myScript.js script to retrieve a malicious app from a server, though the ultimate payload was totally different.

Lastly, we discovered a really related piece of JavaScript on the distribution web sites for the campaigns mentioned on this blogpost, distributing NortirChat, LapizaChat, and ReblyChat. Throughout our investigation, this linkage was independently confirmed by the analysis workforce of the FOFA search engine, who discovered seven of the identical distribution web sites that contained the myScript.js chargeable for downloading Android AridSpy, and attributed this malware to Arid Viper.

We now have not been in a position to hyperlink the JavaScript code utilized in these campaigns to any respectable or open-source mission, which leads us to consider that this script is most definitely particular to numerous Arid Viper campaigns distributing Android malware.

It’s potential that Arid Viper reused this distribution technique, however switched to a brand new software, AridSpy, for its new campaigns, for the reason that (unnamed) malware household the group used earlier than was disclosed and analyzed by varied researchers and safety corporations.

Curiously, we additionally found a distinct model of myScript.js on the AridSpy distribution web site, masquerading as a Palestinian Civil Registry app. On this case, the script had the identical goal however not the identical JavaScript code: as an alternative of downloading AridSpy, this script simply returned a hardcoded hyperlink to AridSpy.

This model of the script relies on a script obtainable on-line, opposite to the sooner variations that seem to make use of a custom-developed myScript.js file. When the sooner variations of myScript.js had been disclosed and attributed to Arid Viper, the menace actors most definitely modified its code to keep away from their new code being linked to the group.

Technical evaluation

Preliminary entry

The distribution mechanism may be very related for all campaigns talked about on this part. With a purpose to achieve preliminary entry to the gadget, the menace actors attempt to persuade their potential sufferer to put in a faux, however practical, app. As soon as the goal clicks the positioning’s Obtain button, myScript.js, hosted on the identical server, is executed to generate the right obtain file path for the malicious AridSpy. This script makes an AJAX request to api.php situated on the identical server and returns a particular file listing and title.

Trojanized messaging functions

Beginning chronologically, we are going to first have a look at the marketing campaign posing as LapizaChat, a malicious Android software that was obtainable for obtain from the devoted lapizachat[.]com web site. This web site was registered on January 16^th, 2022 and is now not lively. Its interface will be seen in Determine 4.

In an open listing on the server, there was not one, however truly three LapizaChat Android apps, saved in numerous directories. One of many apps was a duplicate of the respectable StealthChat: Personal Messaging app and had no malicious performance. It contained the identical respectable messaging code as StealthChat, however with totally different software icon, title, and package deal title. This app has been obtainable on the distribution web site since January 18^th, 2022.

The opposite two apps had been trojanized variations of StealthChat: Personal Messaging bundled with AridSpy’s malicious code. Based mostly on the final modification date, they had been obtainable on the server since July 5^th, 2023 and September 18^th, 2023 respectively, primarily based on the final modification date. The 2 malicious apps are similar to one another; the latter pattern incorporates the identical malicious code, with solely minor, insignificant modifications. It was this model that the sufferer would obtain from the web site after clicking the Obtain Now button. Filenames, final modification dates, and hashes are listed in Desk 1.

Desk 1. Samples obtainable on lapizachat[.]com web site

Filename	Final modified	SHA-1	Description
LapizaChat.apk	2022‑01‑18	D99D9689A7C893AFCE84 04D273D6BA31446C998D	The respectable StealthChat: Personal Messaging software, model 1.8.42 (6008042).
LapizaChat_old.apk	2023‑07‑05	3485A0A51C6DAE251CDA D20B2F659B3815212162	StealthChat trojanized with AridSpy, distributed below the title LapizaChat.
LapizaChat.apk	2023‑09‑18	F49B00896C99EA030DCC A0808B87E414BBDE1549

We recognized two different campaigns that began distributing AridSpy after LapizaChat, this time posing as messaging apps named NortirChat and ReblyChat. They had been distributed (after clicking on the Obtain button) by way of the web sites nortirchats[.]com, registered on September 21^st, 2022, and reblychat[.]com, registered on April 30^th, 2023; see Determine 5.

Just like the earlier case, we had been in a position to retrieve further samples from open directories, together with each the clear and trojanized variations of the messaging functions. NortirChat relies on the respectable Session messaging app, whereas ReblyChat relies on the respectable Voxer Walkie Talkie Messenger. In each circumstances, the trojanized functions have the identical code however the malware builders modified the appliance icon, title, and package deal title. Desk 2 and Desk 3 checklist particulars of the functions retrieved from these servers.

Desk 2. Samples obtainable on nortirchats[.]com web site

Desk 3. Samples obtainable on reblychat[.]com web site

Filename	Final modified	SHA-1	Description
reblychat.apk	2023‑06‑08	FFDD0E387EB3FEF7CBD2 E3DCA5D8924275C3FB94	The respectable Voxer Walkie Talkie Messenger software, model 4.0.2.22408 (3669119).
reblychat-old.apk	2023‑06‑08	A64D73C43B41F9A5B938 AE8558759ADC474005C1	The Voxer Walkie Talkie Messenger app trojanized with AridSpy, distributed below the title ReblyChat.
reblychat.apk	2023‑06‑11	797073511A15EB85C1E9 D8584B26BAA3A0B14C9E

Masquerading as a Palestinian Civil Registry software

Shifting on from trojanizing chat functions in the meanwhile, the operators then launched a marketing campaign distributing an app purporting to be from the Palestinian Civil Registry (السجل المدني الفلسطيني). The malicious app claims to supply common details about the residents of Palestine, akin to title, place of residence, date of beginning, ID quantity, and different info. This marketing campaign gives a malicious Android app obtainable for obtain from palcivilreg[.]com, registered on Might 30^th, 2023; see Determine 6.

Machine translation of the web site from Determine 6: “Palestinian Civil Registry. To seek out out details about any particular person or seek for any particular person’s identification quantity or date of beginning, obtain the appliance to look the Palestinian civil registry.”

This web site is marketed by way of a devoted Fb web page – see Determine 7 – that was created on July 25^th, 2023 and hyperlinks on to palcivilreg[.]com. We now have reported this web page to Fb.

Machine translation of the quilt photograph seen in Determine 7: “Palestinian Civil Registry. Seek for any particular person’s title and acquire his full information. Get date of beginning and age of any particular person. Ease of looking out and coming into the appliance.”

Choosing the تحميل (Obtain, in Arabic; see Determine 6) button executes myScript.js, initiating obtain from a hardcoded URL; see Determine 8. This occasion of myScript.js code is barely modified, in comparison with beforehand talked about campaigns, however achieves the identical outcomes – retrieving a file from a malicious hyperlink. This model of the script will be discovered in lots of tutorials obtainable on-line; considered one of its first occurrences appears to be from February 2019.

The Palestinian Civil Registry app is impressed by an app on Google Play that has been obtainable for obtain since March 2020 and gives the identical performance as claimed on the palcivilreg[.]com web site. The app on Google Play is linked to the web site zezsoft.wuaze[.]com, which permits downloading iOS and Android apps. On the time of this analysis, the iOS software was not obtainable, and the Android app hyperlink refers back to the file-sharing storage web site MediaFire, to not Google Play. This app was now not obtainable from MediaFire, so we aren’t in a position to verify whether or not that model was respectable.

Based mostly on our investigation, the malicious app obtainable on palcivilreg[.]com just isn’t a trojanized model of the app on Google Play; nonetheless, it makes use of that app’s respectable server to retrieve info. Which means Arid Viper was impressed by that app’s performance however created its personal consumer layer that communicates with the respectable server. Most certainly, Arid Viper reverse engineered the respectable Android app from Google Play and used its server for retrieving victims’ information.

Masquerading as a job portal software

The final marketing campaign we recognized distributes AridSpy as an app named تطبيق المشغل (machine translation: Operator software; we check with this because the job alternative app), obtainable for obtain from almoshell[.]web site, registered on August 19^th, 2023. This web site claims to offer a job to anybody who applies by the Android app. On this case, the malicious app just isn’t a trojanized model of any respectable app. When supposedly making use of for a job, AridSpy makes requests to almoshell[.]web site for registered customers. This service runs on a malware distribution web site, so it’s troublesome to determine whether or not any related work presents are returned to the app’s consumer or not. The web site is proven in Determine 9.

The job alternative app has been obtainable for obtain from this distribution web site since August 20^th, 2023; see Determine 10.

Toolset

All analyzed Android apps from these campaigns include related malicious code, and obtain first- and second-stage payloads; our evaluation focuses on the NortirChat and LapizaChat campaigns, the place we had been in a position to receive the ultimate payloads.

Trojanized software

The campaigns largely deploy respectable apps which were trojanized. Within the analyzed LapizaChat and NortirChat circumstances, malicious performance chargeable for downloading a payload is carried out within the apputils subpackage inserted into the respectable messaging apps, as will be seen in Determine 11.

After the preliminary begin of the app, the malware seems to be for put in safety software program primarily based on a hardcoded checklist of dozens of safety functions, and experiences the outcomes to the C&C server. The whole checklist of those apps, together with their package deal names, is in Desk 4.

Desk 4. Checklist of safety apps within the order that they seem within the code

If safety software program on the checklist is put in on the gadget, the malware will ship this info to the C&C server. If the server returns the worth 0, then the first-stage payload is not going to be downloaded. If the server returns the worth 1, then AridSpy proceeds and downloads the first-stage payload. In all circumstances that we noticed, when a safety app was put in on the gadget, the server returned the worth 0 and payloads weren’t downloaded.

AridSpy makes use of trivial string obfuscation, the place every string is said by changing a personality array right into a string. This technique was utilized in each pattern and even within the first revealed evaluation by Zimperium. That very same obfuscation can be utilized within the first- and second-stage payloads. Determine 12 exhibits an instance.

If safety software program just isn’t put in, AridSpy downloads the AES-encrypted first-stage payload from its C&C server. This payload is then decrypted utilizing a hardcoded key, and the potential sufferer is requested to put in it manually. The primary-stage payload impersonates an replace of Google Play providers, as displayed in Determine 13.

First-stage payload

Throughout set up of the malicious replace, the first-stage payload shows app names akin to Play Supervisor or Service Google. This payload works individually, with out the need of getting the trojanized app put in on the identical gadget. Which means if the sufferer uninstalls the preliminary trojanized app, for instance LapizaChat, AridSpy is not going to be in any approach affected.

Performance-wise, the first-stage payload is just like the trojanized software. It’s chargeable for downloading the second-stage payload, which is then dynamically loaded and executed. The primary-stage payload downloads an AES-encrypted second-stage payload from a hardcoded URL and controls its additional execution.

Second-stage payload

The second-stage payload is a Dalvik executable (dex); primarily based on our observations, it all the time has the title prefLog.dex. The malicious performance is carried out on this stage; nonetheless, it’s operated by the first-stage payload, which masses it every time vital.

AridSpy makes use of a Firebase C&C area for receiving instructions, and a distinct, hardcoded C&C area, for information exfiltration. We reported the Firebase servers to Google, because it gives the service.

When payloads are downloaded and executed, AridSpy units listeners to watch when the gadget display screen is on and off. If the sufferer locks or unlocks the telephone, AridSpy will take an image utilizing the entrance digicam and ship it to the exfiltration C&C server. Photos are taken solely whether it is greater than 40 minutes for the reason that final image was taken and the battery degree is above 15%. By default, these footage are taken utilizing the entrance digicam; nonetheless, this may be modified by receiving a command from the Firebase C&C server to make use of the rear digicam. Pictures are archived within the information.zip file on inside storage and uploaded to the exfiltration C&C server.

AridSpy has a function meant to keep away from community detection – particularly C&C communication. It could deactivate itself, as AridSpy states within the code, by altering the exfiltration C&C server used for information add to a dummy hardcoded androidd[.]com area (a presently registered typosquat). This motion happens primarily based on a command obtained from the Firebase C&C server. The dummy area would most likely look extra respectable, just isn’t flagged as malicious, and may not set off community detection methods.

Knowledge exfiltration is initiated both by receiving a command from the Firebase C&C server or when a particularly outlined occasion is triggered. These occasions are outlined in AndroidManifext.xml and are brought about when actions happen, akin to: web connectivity modifications, the app is put in or uninstalled, a telephone name is made or obtained, an SMS message is shipped or obtained, a battery charger is linked or disconnected, or the gadget reboots.

If any of those occasions happens, AridSpy begins to assemble varied sufferer information and uploads it to the exfiltration C&C server. It could accumulate:

• gadget location,
• contact checklist,
• name logs,
• textual content messages,
• thumbnails of pictures,
• thumbnails of recorded movies,
• recorded telephone calls,
• recorded surrounding audio,
• malware-taken pictures,
• file construction of exterior storage,
• six WhatsApp databases (wa.db-wal, wa.db-shm, wa.db, msgstore.db-wal, msgstore.db-shm, msgstore.db) that include exchanged messages and consumer contacts, if the gadget is rooted,
• bookmarks and search historical past from the default browser and Chrome, Samsung Browser, and Firefox apps if put in,
• information within the clipboard,
• information from exterior storage with file measurement smaller than 30 MB and extensions .pdf, .doc, .docx, .xls, .xlsx, .ppt, .pptx, and .opus,
• thumbnails from the Samsung Gallery app saved within the /storage/emulated/0/Android/information/com.sec.android.gallery3d/cache/ listing,
• all obtained notifications,
• Fb Messenger and WhatsApp communication, and
• logs of all textual content seen by misusing Accessibility providers.

Moreover ready for occasions to happen, the Arid Viper operator can extract particular info and add it instantly to the exfiltration C&C server by sending instructions to the compromised gadget. AridSpy can obtain instructions from its Firebase C&C server to acquire information or to regulate the malware. Operators can exfiltrate:

• gadget location,
• contact checklist,
• textual content messages,
• name logs,
• thumbnails of pictures,
• thumbnails of recorded movies,
• a particular picture from exterior storage primarily based on an ID obtained from the Firebase C&C server,
• a particular video from exterior storage primarily based on an ID obtained from the Firebase C&C server,
• recorded audio,
• pictures taken on demand,
• a particular file by file path obtained from the C&C, and
• gadget data akin to whether or not Fb Messenger and WhatsApp apps are put in, gadget storage, battery proportion, web connection, Wi-Fi connection information, display screen on or off standing, and the time zone.

By receiving management instructions, it may well:

• deactivate communication by changing the exfiltration C&C area with the dummy worth androidd[.]com,
• activate communication by changing the dummy androidd[.]com C&C area with one other area title,
• enable information add when on a cellular information plan, and
• change the exfiltration C&C server for information add.

AridSpy can listen in on consumer exercise by keylogging all textual content seen and editable in any software. On prime of that, it particularly focuses on Fb Messenger and WhatsApp communications, that are saved and exfiltrated individually. To perform this activity, it misuses built-in accessibility providers to document all textual content seen and uploads it to the exfiltration C&C server. Examples of saved WhatsApp communications will be seen in Determine 14.

Earlier than collected information is uploaded to the exfiltration C&C server, it’s saved on inside storage, in /information/information//information/information/methods/, that belongs to AridSpy. The obtained contact checklist, SMS, name logs, location, captured keys, file constructions, and different textual content info are saved in plain textual content as JSON information. All exfiltrated information is saved utilizing particular filenames that may include file IDs, filenames, time stamps, location, telephone quantity, and AridSpy model. These values are divided by the delimiter #$&, as will be seen in Determine 15.

All these information from any specific subdirectory are then zipped into information.zip and encrypted utilizing {custom} encryption. Every of the encrypted information makes use of a randomly generated filename with the _Father.zip suffix. This string is hardcoded and appended to each file. The information are then uploaded to the exfiltration C&C server and faraway from the gadget.

Whereas going by the decompiled AridSpy code, we recognized a model quantity, which is used as a part of the filename when exfiltrating sufferer information (#$&V30#$&), additionally seen in Determine 15 (highlighted is the model quantity). The AridSpy model has been altering throughout the campaigns and was included even with its first variant disclosed in 2021. For a few of the AridSpy samples, the model quantity is current within the trojanized app and likewise within the second-stage payload. This model is perhaps totally different, for the reason that downloaded payload will be up to date. In Desk 5, you may see the package deal names and their variations. Some trojanized apps contained the model quantity solely of their payloads, not within the physique of the executable.

Desk 5. Malware variations present in samples

The Model column of the desk means that the malware is recurrently maintained.

It’s price mentioning that the trojanized malicious apps used for the Palestinian Civil Registry and job alternative campaigns have carried out malicious performance that’s then additionally supplied within the second-stage payload. It appears very uncommon to obtain a payload if the identical performance is already included. The duplicated malicious performance doesn’t appear to be an meant conduct, as it isn’t carried out in samples for different campaigns; somewhat, it is perhaps code left over from a time earlier than the malware was up to date to offer two further phases. Even so, these two trojanized apps can obtain instructions and spy on victims without having further payloads. Naturally, the second-stage payload carries the newest updates and malicious code modifications, which will be pushed to different ongoing campaigns.

Conclusion

5 campaigns, most definitely operated by the Arid Viper APT group, distribute Android spy ware, which we have named AridSpy, by way of devoted web sites, with AridSpy’s malicious code implanted into varied trojanized apps. This malware household has two further phases which are downloaded from a C&C server. The aim of the second-stage payload is espionage by way of sufferer information exfiltration. AridSpy additionally has a hardcoded inside model quantity that differs in these 5 campaigns and from different samples disclosed earlier than. This info means that AridSpy is maintained and would possibly obtain updates or performance modifications.

For any inquiries about our analysis revealed on WeLiveSecurity, please contact us at threatintel@eset.com

ESET Analysis presents personal APT intelligence experiences and information feeds. For any inquiries about this service, go to the ESET Risk Intelligence web page.

IoCs

A complete checklist of Indicators of Compromise (IoCs) and samples will be present in our GitHub repository.

Recordsdata

Community

MITRE ATT&CK methods

This desk was constructed utilizing model 15 of the MITRE ATT&CK framework.