Primer paso de la investigacion. Se aportan el .apk, las carpetas con el apk extraido y el apk descompilado. El archivo API_DOCUMENTATION.md es un archivo donde se anotaran los descubrimientos del funcionamiento de la API, y los .py son scripts para probar la funcionalidad de la API con los métodos que vayamos encontrando. Finalmente, los archivos .js son scripts de Frida para extraer informacion de la APP durante la ejecucion.

apk_decompiled/sources/U2/a.java

@@ -0,0 +1,57 @@
+package U2;
+
+import java.util.TimeZone;
+
+/* loaded from: classes3.dex */
+public abstract class a {
+
+    /* renamed from: a, reason: collision with root package name */
+    public static final TimeZone f1791a = TimeZone.getTimeZone("UTC");
+
+    public static boolean a(String str, int i, char c4) {
+        return i < str.length() && str.charAt(i) == c4;
+    }
+
+    /* JADX WARN: Removed duplicated region for block: B:55:0x00f4 A[Catch: IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, TRY_LEAVE, TryCatch #0 {IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, blocks: (B:3:0x0004, B:5:0x0017, B:6:0x0019, B:8:0x0025, B:9:0x0027, B:11:0x0037, B:13:0x003d, B:18:0x0055, B:20:0x0065, B:21:0x0067, B:23:0x0073, B:24:0x0076, B:26:0x007c, B:30:0x0086, B:35:0x0096, B:37:0x009e, B:38:0x00a2, B:40:0x00a8, B:44:0x00b5, B:48:0x00c0, B:53:0x00ee, B:55:0x00f4, B:59:0x01a6, B:59:0x01a6, B:59:0x01a6, B:64:0x0106, B:64:0x0106, B:64:0x0106, B:65:0x0121, B:65:0x0121, B:65:0x0121, B:66:0x0122, B:66:0x0122, B:66:0x0122, B:69:0x013f, B:69:0x013f, B:69:0x013f, B:71:0x014c, B:71:0x014c, B:71:0x014c, B:74:0x0155, B:74:0x0155, B:74:0x0155, B:76:0x0174, B:76:0x0174, B:76:0x0174, B:79:0x0183, B:79:0x0183, B:79:0x0183, B:80:0x01a5, B:80:0x01a5, B:80:0x01a5, B:81:0x012e, B:81:0x012e, B:81:0x012e, B:82:0x01d7, B:82:0x01d7, B:82:0x01d7, B:83:0x01de, B:83:0x01de, B:83:0x01de, B:84:0x00d0, B:85:0x00d3, B:88:0x00bc), top: B:2:0x0004 }] */
+    /* JADX WARN: Removed duplicated region for block: B:82:0x01d7 A[Catch: IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, TryCatch #0 {IndexOutOfBoundsException | NumberFormatException | IllegalArgumentException -> 0x00da, blocks: (B:3:0x0004, B:5:0x0017, B:6:0x0019, B:8:0x0025, B:9:0x0027, B:11:0x0037, B:13:0x003d, B:18:0x0055, B:20:0x0065, B:21:0x0067, B:23:0x0073, B:24:0x0076, B:26:0x007c, B:30:0x0086, B:35:0x0096, B:37:0x009e, B:38:0x00a2, B:40:0x00a8, B:44:0x00b5, B:48:0x00c0, B:53:0x00ee, B:55:0x00f4, B:59:0x01a6, B:59:0x01a6, B:59:0x01a6, B:64:0x0106, B:64:0x0106, B:64:0x0106, B:65:0x0121, B:65:0x0121, B:65:0x0121, B:66:0x0122, B:66:0x0122, B:66:0x0122, B:69:0x013f, B:69:0x013f, B:69:0x013f, B:71:0x014c, B:71:0x014c, B:71:0x014c, B:74:0x0155, B:74:0x0155, B:74:0x0155, B:76:0x0174, B:76:0x0174, B:76:0x0174, B:79:0x0183, B:79:0x0183, B:79:0x0183, B:80:0x01a5, B:80:0x01a5, B:80:0x01a5, B:81:0x012e, B:81:0x012e, B:81:0x012e, B:82:0x01d7, B:82:0x01d7, B:82:0x01d7, B:83:0x01de, B:83:0x01de, B:83:0x01de, B:84:0x00d0, B:85:0x00d3, B:88:0x00bc), top: B:2:0x0004 }] */
+    /*
+        Code decompiled incorrectly, please refer to instructions dump.
+        To view partially-correct add '--show-bad-code' argument
+    */
+    public static java.util.Date b(java.lang.String r17, java.text.ParsePosition r18) {
+        /*
+            Method dump skipped, instructions count: 576
+            To view this dump add '--comments-level debug' option
+        */
+        throw new UnsupportedOperationException("Method not decompiled: U2.a.b(java.lang.String, java.text.ParsePosition):java.util.Date");
+    }
+
+    public static int c(String str, int i, int i4) {
+        int i5;
+        int i6;
+        if (i < 0 || i4 > str.length() || i > i4) {
+            throw new NumberFormatException(str);
+        }
+        if (i < i4) {
+            i6 = i + 1;
+            int digit = Character.digit(str.charAt(i), 10);
+            if (digit < 0) {
+                throw new NumberFormatException("Invalid number: " + str.substring(i, i4));
+            }
+            i5 = -digit;
+        } else {
+            i5 = 0;
+            i6 = i;
+        }
+        while (i6 < i4) {
+            int i7 = i6 + 1;
+            int digit2 = Character.digit(str.charAt(i6), 10);
+            if (digit2 < 0) {
+                throw new NumberFormatException("Invalid number: " + str.substring(i, i4));
+            }
+            i5 = (i5 * 10) - digit2;
+            i6 = i7;
+        }
+        return -i5;
+    }
+}