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Technical Analysis of Bandit Stealer

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Key Points Bandit is a new information stealer that harvests stored credentials from web browsers, FTP clients, email clients, and targets cryptocurrency wallet applications. The malware sends stolen information to a command and control server via Telegram. Bandit implements numerous methods to detect and evade virtual machines and malware sandboxes. Bandit has been marketed and sold as a service on underground criminal forums since April 2023. The malware is written using the Go programming language, which has become increasingly popular with malware developers. Zscaler ThreatLabz has been tracking a new information stealer called Bandit Stealer that emerged in April 2023. Bandit collects sensitive information from victims' machines including cookies, saved login data, and credit card information from more than a dozen web browsers. The stealer also performs credential theft for popular FTP clients and email clients. Lastly, Bandit targets desktop cryptocurrency wallet applications. All of the stolen information is then exfiltrated back to a command and control (C2) server via Telegram. The malware is written in the Go (a.k.a. Golang) programming language and is especially notable with the large number of attempts to evade virtual environments and automated malware analysis platforms. Bandit Stealer is marketed and sold as a service in underground cybercriminal forums as shown in Figure 1. Figure 1: Advertisement for Bandit Stealer on an underground forum Technical Analysis Anti-Virtual Machine & Sandbox Identification Bandit stealer employs a number of anti-analysis techniques to thwart automated and manual analysis. The malware uses the procfs Golang library to read information about running processes and checks for the following process names shown below: Xen Vmware VirtualBox KVM Sandbox QEMU jail If a running process matches any of these names, Bandit will terminate execution. The most recent Bandit samples also check for the presence of a debugger using the Windows API by calling IsDebuggerPresent and CheckRemoteDebuggerPresent. Bandit attempts to elevate permission using the runas command with the username set to Administrator as shown below: C:\Windows\system32\runas.exe runas /user:Administrator C:\Users\saturn\Desktop\Bandit.exe Bandit also executes the Windows Management Interface command-line (WMIC) utility to obtain the Universally Unique Identifier (UUID) of the victim machine and the screen dimensions using the following commands, respectively: wmic csproduct get uuid wmic desktopmonitor get screenheight, screenwidth This information may help threat actors further identify analysis environments. In addition, Bandit uses an extensive list of IP addresses, MAC addresses, computer names, user names, process names to identify virtual environments and associate the environment with security vendors, and therefore avoid exhibiting any malicious behavior. The blacklist information is very similar to that of other prevalent open source stealers including Luna-Grabber, Kyoku-Cookie-Token-Stealer and Creal Stealer. Bandit obtains the system’s external IP address from api.ipify.org and compares it with a list of blacklisted IP addresses shown in the Appendix. Some of these IP addresses belong to antivirus companies, which may be used to block signature updates. Bandit stealer also retrieves the MAC address of the victim machine using the GetAdaptersAddresses Windows API and compares it with a blacklist shown in the Appendix. If there is a match, Bandit exits. Some of these MAC addresses are associated with virtualization software, so the purpose of the blacklist may be to evade malware sandboxes. Bandit Stealer also checks if the victim’s username and computer name are present in additional blacklists, which are obtained using “ cmd /c net session”. The CreateToolhelp32Snapshot Windows API is used to capture the snapshot and traverse along the running process and matches with a list of blacklisted process names and terminates if any process is found executing in the memory shown in the Appendix. Information Stealing Behavior Bandit steals web browser data including saved login information, cookies, history, and credit card information stored in the browser’s user profile. Bandit targets a long list of browsers as shown in Table 1. Yandex Browser Iridium Browser 7Star Browser Vivaldi Browser Google Chrome Orbitum Sputnik uCozMedia Microsoft Edge Torch Web Browser Kometa Browser CentBrowser BraveSoftware Amigo Browser Epic Privacy Browser SeaMonkey browser QupZilla Table 1: Web browsers targeted by Bandit Stealer The SQLite3 library is used to fetch data and the CryptUnprotectData API is used to decrypt cookies and credentials. Credit card information is also stolen, which includes the name, expiration month, year and card number. Bandit also targets desktop cryptocurrency wallets like Electrum, Exodus, MetaMask, Guarda, Binance, Ethereum as shown in Table 2. Coinbase wallet extension Saturn Wallet extension Binance chain wallet extension Coin98 Wallet TronLink Wallet multibit Bitcoin Terra Station Electron Cash Guildwallet extension Electrum-btcp MetaMask extension Bither Bitcoin wallet ronin wallet extension multidoge coin Kardiachain wallet extension LiteCoin Jaxx liberty Wallet Dash Wallet Math Wallet extension Ethereum Bitpay wallet extension Exodus Nifty Wallet extension Atomic Armory Bytecoin Wallet Coinomi wallet Monero wallet dogecoin Table 2: Cryptocurrency wallets targeted by Bandit Stealer Bandit also has the capability to harvest keystrokes and steal clipboard data. Recent samples of Bandit also target credentials in the following File Transfer Protocol Client (FTP) applications shown in Table 3. BlazeFTP NovaFTP Staff-FTP EasyFTP DeluxeFTP ALFTP GoFTP 32BitFtp Table 3: FTP client applications targeted by Bandit Bandit also targets login information for the email clients shown in Table 4. MailSpring Mailbird Opera Mail Pocomail Table 4: Email client applications targeted by Bandit Stolen data is saved in various files inside a sub-folder in the %appdata%\local directory as shown in Figure 2. The sub-folder name is based on the country code and the IP address in the format [country_code][ip_address]. Figure 2: Example information collected by Bandit Stealer The content of the USERINFO.txt contains a Bandit Stealer header followed by system information as shown in Figure 3. Figure 3: Example content in the Bandit USERINFO.txt file Network Communication Bandit uses the cURL utility which is installed by default since Windows 10 v1803 to transfer data using HTTP, FTP, SMTP and more. Bandit stealer abuses pastebin.com for downloading the blacklist configuration information from a hardcoded URL as shown in Figure 4. Figure 4: Bandit Stealer blacklist configuration downloaded from Pastebin After Bandit finishes data collection, this information is sent to the threat actor via Telegram as shown in Figure 5. Figure 5: Data stolen by Bandit sent to a Telegram channel The Bandit threat actor has automated the parsing and extraction of the data and responds back with a JSON encoded structure as shown in Figure 6. Figure 6: Example Bandit C2 response Conclusion Bandit Stealer is continuously updated with new features to enhance its data collection functionality. Most recently, Bandit has added support to steal FTP and email credentials. Bandit is also capable of expanding its anti-analysis features with a dynamic configuration downloaded from Pastebin. The abuse of Telegram as a C2 server has also become an increasingly popular technique to evade network-based signatures and make takedown efforts more difficult. All of these factors set up Bandit Stealer to be a potential threat for the foreseeable future. Zscaler Coverage Zscaler has ensured coverage for the payloads seen in these attacks via advanced threat signatures as well as Zscaler’s advanced cloud sandbox. Figure 7: The Zscaler Cloud Sandbox successfully detected the malware Zscaler's multilayered cloud security platform detects indicators at various levels, as shown below: Win64_PWS_Bandit Indicators of Compromise (IOCs) MD5 Hash Values Description 17c697da407acacadcaa8fb5c4885179 Bandit Stealer fdb111c9e0c6b1a94e2bf22131e4266d Bandit Stealer 700e57847516d1f3e4ebf02e015e9f8d Bandit Stealer 329562ce914d3d5998ac071333e43c1c Bandit Stealer 4ab55868b65dc8f16d9d62edfd1893fa Bandit Stealer 34323d65b744664567c06f8c6076a6b1 Bandit Stealer 2207a896e3e2ac5dae04643e56767dcd Bandit Stealer caf4884072724f1d75a6288f27e8e8fe Bandit Stealer Appendix IP addresses blacklisted by Bandit Stealer 88.132.231.71 95.25.204.90 34.105.72.241 193.128.114.45 78.139.8.50 34.145.89.174 109.74.154.92 95.25.81.24 20.99.160.173 109.74.154.90 213.33.142.50 92.211.52.62 88.153.199.169 109.145.173.169 109.74.154.91 88.132.227.238 84.147.62.12 34.141.146.114 93.216.75.209 35.199.6.13 194.154.78.160 212.119.227.151 192.87.28.103 80.211.0.97 92.211.109.160 195.239.51.59 88.132.226.203 34.85.253.170 195.74.76.222 192.40.57.234 195.181.175.105 23.128.248.46 188.105.91.116 64.124.12.162 88.132.225.100 35.229.69.227 34.105.183.68 34.142.74.220 92.211.192.144 34.138.96.23 92.211.55.199 188.105.91.173 34.83.46.130 192.211.110.74 79.104.209.33 109.74.154.91 188.105.91.143 35.237.47.12 178.239.165.70 34.141.245.25 34.85.243.241 87.166.50.213 34.105.0.27 34.145.195.58 193.225.193.201 34.253.248.228 35.192.93.107 195.239.51.3 84.147.54.113 212.119.227.167 MAC addresses blacklisted by Bandit Stealer 00:15:5d:00:07:34 00:50:56:b3:14:59 16:ef:22:04:af:76 42:01:0a:8a:00:22 00:e0:4c:b8:7a:58 ea:02:75:3c:90:9f 00:15:5d:23:4c:ad 00:1b:21:13:32:51 00:0c:29:2c:c1:21 00:e0:4c:44:76:54 1a:6c:62:60:3b:f4 a6:24:aa:ae:e6:12 00:25:90:65:39:e4 ac:1f:6b:d0:4d:e4 00:15:5d:00:00:1d 08:00:27:45:13:10 c8:9f:1d:b6:58:e4 52:54:00:3b:78:24 00:50:56:a0:cd:a8 00:1b:21:13:26:44 00:25:90:36:65:0c 00:50:56:b3:50:de 00:50:56:b3:fa:23 3c:ec:ef:43:fe:de 00:15:5d:00:00:f3 7e:05:a3:62:9c:4d 52:54:00:a0:41:92 d4:81:d7:ed:25:54 2e:b8:24:4d:f7:de 52:54:00:b3:e4:71 00:50:56:b3:f6:57 00:25:90:36:65:38 00:15:5d:13:6d:0c 90:48:9a:9d:d5:24 00:e0:4c:56:42:97 00:03:47:63:8b:de 00:50:56:a0:dd:00 00:50:56:b3:3b:a6 ca:4d:4b:ca:18:cc 00:15:5d:00:05:8d 00:15:5d:13:66:ca 92:4c:a8:23:fc:2e f6:a5:41:31:b2:78 00:0c:29:52:52:50 56:e8:92:2e:76:0d 5a:e2:a6:a4:44:db d6:03:e4:ab:77:8e 00:50:56:b3:42:33 ac:1f:6b:d0:48:fe 00:50:56:ae:6f:54 00:50:56:ae:b2:b0 3c:ec:ef:44:01:0c 00:e0:4c:94:1f:20 42:01:0a:96:00:33 00:50:56:b3:94:cb 06:75:91:59:3e:02 00:15:5d:00:05:d5 00:50:56:97:a1:f8 42:01:0a:8e:00:22 42:01:0a:8a:00:33 00:e0:4c:4b:4a:40 5e:86:e4:3d:0d:f6 00:50:56:b3:4c:bf ea:f6:f1:a2:33:76 42:01:0a:8a:00:22 00:50:56:b3:ea:ee 00:50:56:b3:09:9e ac:1f:6b:d0:4d:98 00:1b:21:13:15:20 3e:53:81:b7:01:13 00:50:56:b3:38:88 1e:6c:34:93:68:64 00:15:5d:00:06:43 00:50:56:97:ec:f2 00:50:56:a0:d0:fa 00:50:56:a0:61:aa 00:15:5d:1e:01:c8 00:e0:4c:b3:5a:2a 00:50:56:b3:91:c8 42:01:0a:96:00:22 00:50:56:b3:38:68 12:f8:87:ab:13:ec 3e:c1:fd:f1:bf:71 00:50:56:b3:21:29 60:02:92:3d:f1:69 00:50:56:a0:38:06 00:50:56:a0:6d:86 00:15:5d:00:00:b3 00:e0:4c:7b:7b:86 2e:62:e8:47:14:49 00:50:56:a0:af:75 96:2b:e9:43:96:76 00:e0:4c:46:cf:01 00:0d:3a:d2:4f:1f 00:50:56:b3:dd:03 b4:a9:5a:b1:c6:fd 42:85:07:f4:83:d0 60:02:92:66:10:79 c2:ee:af:fd:29:21 d4:81:d7:87:05:ab 56:b0:6f:ca:0a:e7 00:50:56:a0:d7:38 00:50:56:b3:ee:e1 ac:1f:6b:d0:49:86 12:1b:9e:3c:a6:2c be:00:e5:c5:0c:e5 00:50:56:a0:84:88 52:54:00:8b:a6:08 00:15:5d:00:1c:9a 00:50:56:a0:59:10 00:1b:21:13:32:20 00:0c:29:05:d8:6e 00:15:5d:00:1a:b9 00:50:56:a0:06:8d 3c:ec:ef:44:00:d0 00:23:cd:ff:94:f0 b6:ed:9d:27:f4:fa 00:e0:4c:cb:62:08 00:50:56:ae:e5:d5 00:e0:4c:d6:86:77 00:15:5d:00:01:81 4e:81:81:8e:22:4e 00:50:56:97:f6:c8 3c:ec:ef:44:01:aa 4e:79:c0:d9:af:c3 08:00:27:3a:28:73 52:54:00:ab:de:59 00:15:5d:23:4c:a3 00:15:5d:b6:e0:cc 00:15:5d:00:00:c3 00:50:56:b3:9e:9e 00:1b:21:13:33:55 00:15:5d:00:02:26 00:50:56:a0:45:03 00:50:56:a0:39:18 00:15:5d:00:00:a4 00:50:56:b3:05:b4 12:8a:5c:2a:65:d1 32:11:4d:d0:4a:9e 00:50:56:ae:5d:ea 1c:99:57:1c:ad:e4 00:25:90:36:f0:3b 00:50:56:b3:d0:a7 94:de:80:de:1a:35 00:1b:21:13:21:26 Hardware IDs blacklisted by Bandit Stealer 7AB5C494-39F5-4941-9163-47F54D6D5016 050C3342-FADD-AEDF-EF24-C6454E1A73C9 BB233342-2E01-718F-D4A1-E7F69D026428 79AF5279-16CF-4094-9758-F88A616D81B4 03DE0294-0480-05DE-1A06-350700080009 4DC32042-E601-F329-21C1-03F27564FD6C 9921DE3A-5C1A-DF11-9078-563412000026 FF577B79-782E-0A4D-8568-B35A9B7EB76B 11111111-2222-3333-4444-555555555555 DEAEB8CE-A573-9F48-BD40-62ED6C223F20 CC5B3F62-2A04-4D2E-A46C-AA41B7050712 08C1E400-3C56-11EA-8000-3CECEF43FEDE 6F3CA5EC-BEC9-4A4D-8274-11168F640058 05790C00-3B21-11EA-8000-3CECEF4400D0 00000000-0000-0000-0000-AC1F6BD04986 6ECEAF72-3548-476C-BD8D-73134A9182C8 ADEEEE9E-EF0A-6B84-B14B-B83A54AFC548 5EBD2E42-1DB8-78A6-0EC3-031B661D5C57 C249957A-AA08-4B21-933F-9271BEC63C85 49434D53-0200-9036-2500-369025003865 4C4C4544-0050-3710-8058-CAC04F59344A 9C6D1742-046D-BC94-ED09-C36F70CC9A91 BE784D56-81F5-2C8D-9D4B-5AB56F05D86E 119602E8-92F9-BD4B-8979-DA682276D385 00000000-0000-0000-0000-AC1F6BD04972 907A2A79-7116-4CB6-9FA5-E5A58C4587CD ACA69200-3C4C-11EA-8000-3CECEF4401AA 12204D56-28C0-AB03-51B7-44A8B7525250 00000000-0000-0000-0000-000000000000 A9C83342-4800-0578-1EE8-BA26D2A678D2 3F284CA4-8BDF-489B-A273-41B44D668F6D 921E2042-70D3-F9F1-8CBD-B398A21F89C6 5BD24D56-789F-8468-7CDC-CAA7222CC121 D7382042-00A0-A6F0-1E51-FD1BBF06CD71 BB64E044-87BA-C847-BC0A-C797D1A16A50 D8C30328-1B06-4611-8E3C-E433F4F9794E 49434D53-0200-9065-2500-65902500E439 1D4D3342-D6C4-710C-98A3-9CC6571234D5 2E6FB594-9D55-4424-8E74-CE25A25E36B0 00000000-0000-0000-0000-50E5493391EF 49434D53-0200-9036-2500-36902500F022 CE352E42-9339-8484-293A-BD50CDC639A5 42A82042-3F13-512F-5E3D-6BF4FFFD8518 00000000-0000-0000-0000-AC1F6BD04D98 777D84B3-88D1-451C-93E4-D235177420A7 60C83342-0A97-928D-7316-5F1080A78E72 38AB3342-66B0-7175-0B23-F390B3728B78 4CB82042-BA8F-1748-C941-363C391CA7F3 49434D53-0200-9036-2500-369025000C65 02AD9898-FA37-11EB-AC55-1D0C0A67EA8A 48941AE9-D52F-11DF-BBDA-503734826431 B6464A2B-92C7-4B95-A2D0-E5410081B812 B1112042-52E8-E25B-3655-6A4F54155DBF DBCC3514-FA57-477D-9D1F-1CAF4CC92D0F 032E02B4-0499-05C3-0806-3C0700080009 FA8C2042-205D-13B0-FCB5-C5CC55577A35 00000000-0000-0000-0000-AC1F6BD048FE FED63342-E0D6-C669-D53F-253D696D74DA DD9C3342-FB80-9A31-EB04-5794E5AE2B4C C6B32042-4EC3-6FDF-C725-6F63914DA7C7 EB16924B-FB6D-4FA1-8666-17B91F62FB37 2DD1B176-C043-49A4-830F-C623FFB88F3C E08DE9AA-C704-4261-B32D-57B2A3993518 FCE23342-91F1-EAFC-BA97-5AAE4509E173 A15A930C-8251-9645-AF63-E45AD728C20C 4729AEB0-FC07-11E3-9673-CE39E79C8A00 07E42E42-F43D-3E1C-1C6B-9C7AC120F3B9 CF1BE00F-4AAF-455E-8DCD-B5B09B6BFA8F 67E595EB-54AC-4FF0-B5E3-3DA7C7B547E3 84FE3342-6C67-5FC6-5639-9B3CA3D775A1 88DC3342-12E6-7D62-B0AE-C80E578E7B07 365B4000-3B25-11EA-8000-3CECEF44010C C7D23342-A5D4-68A1-59AC-CF40F735B363 DBC22E42-59F7-1329-D9F2-E78A2EE5BD0D 5E3E7FE0-2636-4CB7-84F5-8D2650FFEC0E 63FA3342-31C7-4E8E-8089-DAFF6CE5E967 63203342-0EB0-AA1A-4DF5-3FB37DBB0670 CEFC836C-8CB1-45A6-ADD7-209085EE2A57 96BB3342-6335-0FA8-BA29-E1BA5D8FEFBE 8DA62042-8B59-B4E3-D232-38B29A10964A 44B94D56-65AB-DC02-86A0-98143A7423BF A7721742-BE24-8A1C-B859-D7F8251A83D3 0934E336-72E4-4E6A-B3E5-383BD8E938C3 3A9F3342-D1F2-DF37-68AE-C10F60BFB462 6608003F-ECE4-494E-B07E-1C4615D1D93C 3F3C58D1-B4F2-4019-B2A2-2A500E96AF2E 12EE3342-87A2-32DE-A390-4C2DA4D512E9 F5744000-3C78-11EA-8000-3CECEF43FEFE D9142042-8F51-5EFF-D5F8-EE9AE3D1602A D2DC3342-396C-6737-A8F6-0C6673C1DE08 38813342-D7D0-DFC8-C56F-7FC9DFE5C972 AF1B2042-4B90-0000-A4E4-632A1C8C7EB1 49434D53-0200-9036-2500-369025003AF0 EADD1742-4807-00A0-F92E-CCD933E9D8C1 FE455D1A-BE27-4BA4-96C8-967A6D3A9661 4D4DDC94-E06C-44F4-95FE-33A1ADA5AC27 8B4E8278-525C-7343-B825-280AEBCD3BCB Usernames blacklisted by Bandit Stealer WDAGUtilityAccount server 8VizSM Abby BvJChRPnsxn w0fjuOVmCcP5A hmarc Harry Johnson lmVwjj9b patex SqgFOf3G PqONjHVwexsS RDhJ0CNFevzX Lucas 3u2v9m8 kEecfMwgj mike Julia Frank PateX HEUeRzl 8Nl0ColNQ5bq h7dk1xPr fred Lisa Louise RGzcBUyrznReg John User01 PxmdUOpVyx george test Computer names blacklisted by Bandit Stealer BEE7370C-8C0C-4 WILEYPC DESKTOP-CBGPFEE DESKTOP-NAKFFMT WORK SERVER-PC WIN-5E07COS9ALR 6C4E733F-C2D9-4 TIQIYLA9TW5M B30F0242-1C6A-4 RALPHS-PC DESKTOP-KALVINO DESKTOP-VRSQLAG DESKTOP-WG3MYJS COMPNAME_4047 Q9IATRKPRH DESKTOP-7XC6GEZ DESKTOP-19OLLTD XC64ZB DESKTOP-5OV9S0O DESKTOP-DE369SE DESKTOP-D019GDM QarZhrdBpj EA8C2E2A-D017-4 DESKTOP-WI8CLET ORELEEPC AIDANPC SERVER1 ARCHIBALDPC LUCAS-PC LISA-PC JULIA-PC MARCI-PC JOHN-PC d1bnJkfVlH DESKTOP-1PYKP29 DESKTOP-B0T93D6 NETTYPC DESKTOP-1Y2433R DESKTOP-BUGIO Process names blacklisted by Bandit Stealer httpdebuggerui vmwareuser wireshark vgauthservice fiddler vmacthlp regedit x96dbg cmd vmsrvc taskmgr x32dbg vboxservice vmusrvc df5serv prl_cc processhacker prl_tools vboxtray xenservice vmtoolsd qemu-ga vmwaretray joeboxcontrol ida64 ksdumperclient ollydbg ksdumper pestudio joeboxserver

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