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 through 5 devoted web sites.
• AridSpy’s code is in some instances bundled into purposes 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 knowledge 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, also called APT-C-23, Desert Falcons, or Two-tailed Scorpion, is a cyberespionage group that has been energetic since a minimum of 2013. Identified for concentrating on international locations within the Center East, the group has drawn consideration through the years for its huge arsenal of malware for Android, iOS, and Home windows platforms. We reported on the group and its then-newest spyware and adware in a earlier blogpost.

Overview

ESET Analysis recognized 5 Arid Viper campaigns concentrating on Android customers. These campaigns delivered malware through devoted web sites from which victims may obtain and manually set up an Android software. Three apps offered on these web sites are respectable apps trojanized with malicious code that we named AridSpy, whose function is espionage. You may 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 incidence 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 purposes, 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 right now.

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, based mostly 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 establish 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 energetic; 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 seek advice from this because the job alternative app) and السجل المدني الفلسطيني (machine translation: Palestinian Civil Registry) apps. We found the next distribution web sites through 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 staff printed 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 numerous variations of AridSpy. The next two have been beforehand unknown to us:

• clemochat[.]com
• voevanil[.]com

On this blogpost, we concentrate on AridSpy payloads that we may acquire from all of the confirmed energetic distribution web sites listed above.

Notice that these malicious apps have by no means been supplied by way of 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 possibility 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 spyware and adware cases registered in Palestine have 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, based mostly 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 novel, 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 comparable 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 staff 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’ve not been in a position to hyperlink the JavaScript code utilized in these campaigns to any respectable or open-source venture, which leads us to imagine that this script is more than likely particular to numerous Arid Viper campaigns distributing Android malware.

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

Apparently, we additionally found a distinct model of myScript.js on the AridSpy distribution website, masquerading as a Palestinian Civil Registry app. On this case, the script had the identical function however not the identical JavaScript code: as a substitute of downloading AridSpy, this script simply returned a hardcoded hyperlink to AridSpy.

This model of the script is predicated on a script accessible 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 have been disclosed and attributed to Arid Viper, the menace actors more than likely modified its code to keep away from their new code being related to the group.

Technical evaluation

Preliminary entry

The distribution mechanism could be very comparable for all campaigns talked about on this part. To be able to acquire preliminary entry to the machine, the menace actors attempt to persuade their potential sufferer to put in a faux, however useful, 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 purposes

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

In an open listing on the server, there was not one, however truly three LapizaChat Android apps, saved in several 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 accessible on the distribution web site since January 18^th, 2022.

The opposite two apps have been trojanized variations of StealthChat: Personal Messaging bundled with AridSpy’s malicious code. Based mostly on the final modification date, they have been accessible on the server since July 5^th, 2023 and September 18^th, 2023 respectively, based mostly on the final modification date. The 2 malicious apps are similar to one another; the latter pattern comprises the identical malicious code, with solely minor, insignificant adjustments. 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 accessible 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 have been distributed (after clicking on the Obtain button) through 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 have been in a position to retrieve further samples from open directories, together with each the clear and trojanized variations of the messaging purposes. NortirChat is predicated on the respectable Session messaging app, whereas ReblyChat is predicated on the respectable Voxer Walkie Talkie Messenger. In each instances, the trojanized purposes have the identical code however the malware builders modified the applying icon, title, and package deal title. Desk 2 and Desk 3 checklist particulars of the purposes retrieved from these servers.

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

Desk 3. Samples accessible 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

Transferring on from trojanizing chat purposes in the intervening time, 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 normal details about the residents of Palestine, reminiscent of title, place of residence, date of beginning, ID quantity, and different info. This marketing campaign offers a malicious Android app accessible 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 applying to look the Palestinian civil registry.”

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

Machine translation of the duvet picture seen in Determine 7: “Palestinian Civil Registry. Seek for any particular person’s title and procure his full knowledge. Get date of beginning and age of any particular person. Ease of looking out and getting into the applying.”

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 may be discovered in lots of tutorials accessible on-line; one in every 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 accessible for obtain since March 2020 and offers the identical performance as claimed on the palcivilreg[.]com website. 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 accessible, and the Android app hyperlink refers back to the file-sharing storage website MediaFire, to not Google Play. This app was now not accessible from MediaFire, so we’re not in a position to verify whether or not that model was respectable.

Based mostly on our investigation, the malicious app accessible on palcivilreg[.]com will not be a trojanized model of the app on Google Play; nevertheless, 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 shopper layer that communicates with the respectable server. Most probably, Arid Viper reverse engineered the respectable Android app from Google Play and used its server for retrieving victims’ knowledge.

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 seek advice from this because the job alternative app), accessible 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 way of the Android app. On this case, the malicious app will not be 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 establish whether or not any related work gives are returned to the app’s consumer or not. The web site is proven in Determine 9.

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

Toolset

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

Trojanized software

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

After the preliminary begin of the app, the malware seems to be for put in safety software program based mostly on a hardcoded checklist of dozens of safety purposes, and studies 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. Record of safety apps within the order that they seem within the code

If safety software program on the checklist is put in on the machine, the malware will ship this info to the C&C server. If the server returns the worth 0, then the first-stage payload won’t be downloaded. If the server returns the worth 1, then AridSpy proceeds and downloads the first-stage payload. In all instances that we noticed, when a safety app was put in on the machine, 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 printed 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 will not be 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 reminiscent of Play Supervisor or Service Google. This payload works individually, with out the need of getting the trojanized app put in on the identical machine. Which means if the sufferer uninstalls the preliminary trojanized app, for instance LapizaChat, AridSpy won’t be in any means affected.

Performance-wise, the first-stage payload is much 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); based mostly on our observations, it all the time has the title prefLog.dex. The malicious performance is carried out on this stage; nevertheless, it’s operated by the first-stage payload, which masses it at any time when needed.

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

When payloads are downloaded and executed, AridSpy units listeners to observe when the machine display is on and off. If the sufferer locks or unlocks the cellphone, AridSpy will take an image utilizing the entrance digicam and ship it to the exfiltration C&C server. Footage are taken solely whether it is greater than 40 minutes because the final image was taken and the battery degree is above 15%. By default, these photos are taken utilizing the entrance digicam; nevertheless, 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 knowledge.zip file on inside storage and uploaded to the exfiltration C&C server.

AridSpy has a characteristic supposed to keep away from community detection – particularly C&C communication. It could actually deactivate itself, as AridSpy states within the code, by altering the exfiltration C&C server used for knowledge add to a dummy hardcoded androidd[.]com area (a at present registered typosquat). This motion happens based mostly on a command acquired from the Firebase C&C server. The dummy area would in all probability look extra respectable, will not be flagged as malicious, and may not set off community detection techniques.

Information 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 prompted when actions happen, reminiscent of: web connectivity adjustments, the app is put in or uninstalled, a cellphone name is made or acquired, an SMS message is shipped or acquired, a battery charger is related or disconnected, or the machine reboots.

If any of those occasions happens, AridSpy begins to collect numerous sufferer knowledge and uploads it to the exfiltration C&C server. It could actually acquire:

• machine location,
• contact checklist,
• name logs,
• textual content messages,
• thumbnails of images,
• thumbnails of recorded movies,
• recorded cellphone calls,
• recorded surrounding audio,
• malware-taken images,
• 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 comprise exchanged messages and consumer contacts, if the machine is rooted,
• bookmarks and search historical past from the default browser and Chrome, Samsung Browser, and Firefox apps if put in,
• knowledge within the clipboard,
• recordsdata 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/knowledge/com.sec.android.gallery3d/cache/ listing,
• all acquired 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 machine. AridSpy can obtain instructions from its Firebase C&C server to acquire knowledge or to regulate the malware. Operators can exfiltrate:

• machine location,
• contact checklist,
• textual content messages,
• name logs,
• thumbnails of images,
• thumbnails of recorded movies,
• a particular picture from exterior storage based mostly on an ID acquired from the Firebase C&C server,
• a particular video from exterior storage based mostly on an ID acquired from the Firebase C&C server,
• recorded audio,
• pictures taken on demand,
• a particular file by file path acquired from the C&C, and
• machine data reminiscent of whether or not Fb Messenger and WhatsApp apps are put in, machine storage, battery share, web connection, Wi-Fi connection knowledge, display 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 knowledge add when on a cellular knowledge plan, and
• change the exfiltration C&C server for knowledge 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 job, 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 may be seen in Determine 14.

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

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

Whereas going by way of the decompiled AridSpy code, we recognized a model quantity, which is used as a part of the filename when exfiltrating sufferer knowledge (#$&V30#$&), 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 among the AridSpy samples, the model quantity is current within the trojanized app and in addition within the second-stage payload. This model may be totally different, because the downloaded payload may 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 usually maintained.

It’s value 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 offered 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 supposed conduct, as it’s not carried out in samples for different campaigns; reasonably, it may be 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 most recent updates and malicious code adjustments, which may be pushed to different ongoing campaigns.

Conclusion

5 campaigns, more than likely operated by the Arid Viper APT group, distribute Android spyware and adware, which we have named AridSpy, through devoted web sites, with AridSpy’s malicious code implanted into numerous 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 through sufferer knowledge 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 may obtain updates or performance adjustments.

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

ESET Analysis gives personal APT intelligence studies and knowledge 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 may be present in our GitHub repository.

Information

Community

MITRE ATT&CK methods

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