CVE-2021-21386 (published 2021-03-24T21:15Z)

APKLeaks is an open-source project for scanning APK file for URIs, endpoints & secrets. APKLeaks prior to v2.0.3 allows remote attackers to execute arbitrary OS commands via package name inside application manifest. An attacker could include arguments that allow unintended commands or code to be executed, allow sensitive data to be read or modified or could cause other unintended behavior through malicious package name. The problem is fixed in version v2.0.6-dev and above.

Severity: HIGH
CVSS v2 base score: 10.0 (AV:N/AC:L/Au:N/C:C/I:C/A:C)
CVSS v3 base score: 9.8, CRITICAL (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Weakness information:
cwe_id: CWE-78
cwe_name: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
description: The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
extended_description: 
		   This weakness can lead to a vulnerability in environments in which the attacker does not have direct access to the operating system, such as in web applications. Alternately, if the weakness occurs in a privileged program, it could allow the attacker to specify commands that normally would not be accessible, or to call alternate commands with privileges that the attacker does not have. The problem is exacerbated if the compromised process does not follow the principle of least privilege, because the attacker-controlled commands may run with special system privileges that increases the amount of damage.
            There are at least two subtypes of OS command injection:
               
				 The application intends to execute a single, fixed program that is under its own control. It intends to use externally-supplied inputs as arguments to that program. For example, the program might use system("nslookup [HOSTNAME]") to run nslookup and allow the user to supply a HOSTNAME, which is used as an argument. Attackers cannot prevent nslookup from executing. However, if the program does not remove command separators from the HOSTNAME argument, attackers could place the separators into the arguments, which allows them to execute their own program after nslookup has finished executing.
				 The application accepts an input that it uses to fully select which program to run, as well as which commands to use. The application simply redirects this entire command to the operating system. For example, the program might use "exec([COMMAND])" to execute the [COMMAND] that was supplied by the user. If the COMMAND is under attacker control, then the attacker can execute arbitrary commands or programs. If the command is being executed using functions like exec() and CreateProcess(), the attacker might not be able to combine multiple commands together in the same line.
               
            From a weakness standpoint, these variants represent distinct programmer errors. In the first variant, the programmer clearly intends that input from untrusted parties will be part of the arguments in the command to be executed. In the second variant, the programmer does not intend for the command to be accessible to any untrusted party, but the programmer probably has not accounted for alternate ways in which malicious attackers can provide input.
         
         
cwe_id: CWE-88
cwe_name: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
description: The product constructs a string for a command to be executed by a separate component
in another control sphere, but it does not properly delimit the
intended arguments, options, or switches within that command string.
extended_description: 
            When creating commands using interpolation into a string, developers may assume that only the arguments/options that they specify will be processed.  This assumption may be even stronger when the programmer has encoded the command in a way that prevents separate commands from being provided maliciously, e.g. in the case of shell metacharacters.  When constructing the command, the developer may use whitespace or other delimiters that are required to separate arguments when the command. However, if an attacker can provide an untrusted input that contains argument-separating delimiters, then the resulting command will have more arguments than intended by the developer.  The attacker may then be able to change the behavior of the command.  Depending on the functionality supported by the extraneous arguments, this may have security-relevant consequences.
         
         

Fix information:
repo_url: https://github.com/dwisiswant0/apkleaks
commit_details: repo_url: https://github.com/dwisiswant0/apkleaks
author: Dwi Siswanto
author_date: 2021-03-14 22:25:42+07:00
msg: Escapes decompiling arguments
repository: repo_url: https://github.com/dwisiswant0/apkleaks
repo_name: dwisiswant0/apkleaks
description: Scanning APK file for URIs, endpoints & secrets.
repo_language: Python
owner: dwisiswant0
file_changes: filename: apkleaks.py
change_type: ModificationType.MODIFY
diff: @@ -2,6 +2,7 @@
 from apkleaks.colors import clr
 from contextlib import closing
 from distutils.spawn import find_executable
+from pipes import quote
 from pyaxmlparser import APK
 from urllib.request import urlopen
 from zipfile import ZipFile
@@ -84,8 +85,9 @@ class APKLeaks:
 					classes.write(zipped.read("classes.dex"))
 			except Exception as e:
 				sys.exit(self.writeln(str(e), clr.WARNING))
-		dec = "%s %s -d %s --deobf" % (self.jadx, dex, self.tempdir)
-		os.system(dec)
+		args = [self.jadx, dex, "-d", self.tempdir, "--deobf"]
+		comm = "%s" % (" ".join(quote(arg) for arg in args))
+		os.system(comm)
 		return self.tempdir
 
 	def unique(self, list): 

programming_language: Python