On Feb 12th 2013, FireEye announced the discovery of an Adobe Reader 0-day exploit which is used to drop a previously unknown, advanced piece of malware. We called this new malware ?ItaDuke because it reminded us of Duqu and because of the ancient Italian comments in the shellcode copied from Dante Alighieri-s ?Divine Comedy.
How To Exploit BackDoor PDF Files
Once they are downloaded to the machine, they can fetch a larger backdoor which carries out the cyberespionage activities, through functions such as copy file, move file, remove file, make directory, kill process and of course, download and execute new malware and lateral movement tools.
Roaming Mantis (a.k.a Shaoye) is a long-term cyberattack campaign that uses malicious Android package (APK) files to control infected Android devices and steal data. In 2022, we observed a DNS changer function implemented in its Android malware Wroba.o.
Over the years the adobe reader has had a bunch of vulnerabilities which are exploited by the hackers. Hackers embed payload in PDF which looks legitimate and maybe important in the eyes of the victim. One factor that makes this hack successful is due to the fact that adobe reader is a common PDF reader in computers around the world. Over time, Linux tools have been developed to embed payload in PDF with the main focus being on simplifying the process of embedding the payload.
A backdoor is a malware type that negates normal authentication procedures to access a system. As a result, remote access is granted to resources within an application, such as databases and file servers, giving perpetrators the ability to remotely issue system commands and update malware.
The most prevalent backdoor installation method involves remote file inclusion (RFI), an attack vector that exploits vulnerabilities within applications that dynamically reference external scripts. In an RFI scenario, the referencing function is tricked into downloading a backdoor trojan from a remote host.
Perpetrators typically identify targets using scanners, which locate websites having unpatched or outdated components that enable file injection. A successful scanner then abuses the vulnerability to install the backdoor on the underlying server. Once installed, it can be accessed at any time, even if the vulnerability enabling its injection has since been patched.
Detection is further complicated since many applications are built on external frameworks that use third-party plugins; these are sometimes laden with vulnerabilities or built-in backdoors. Scanners that rely on heuristic and signature-based rules might not be able to detect hidden code in such frameworks.
Even if a backdoor is detected, typical mitigation methods (or even a system reinstallation) are unlikely to remove it from an application. This is particularly true for backdoors having a persistent presence in rewritable memory.
A backdoor may take the form of a hidden part of a program,[3] a separate program (e.g. Back Orifice may subvert the system through a rootkit), code in the firmware of the hardware,[4] or parts of an operating system such as Windows.[5][6][7] Trojan horses can be used to create vulnerabilities in a device. A Trojan horse may appear to be an entirely legitimate program, but when executed, it triggers an activity that may install a backdoor.[8] Although some are secretly installed, other backdoors are deliberate and widely known. These kinds of backdoors have "legitimate" uses such as providing the manufacturer with a way to restore user passwords.
Default passwords (or other default credentials) can function as backdoors if they are not changed by the user. Some debugging features can also act as backdoors if they are not removed in the release version.[10]
In 1993, the United States government attempted to deploy an encryption system, the Clipper chip, with an explicit backdoor for law enforcement and national security access. The chip was unsuccessful.[11]
The threat of backdoors surfaced when multiuser and networked operating systems became widely adopted. Petersen and Turn discussed computer subversion in a paper published in the proceedings of the 1967 AFIPS Conference.[12] They noted a class of active infiltration attacks that use "trapdoor" entry points into the system to bypass security facilities and permit direct access to data. The use of the word trapdoor here clearly coincides with more recent definitions of a backdoor. However, since the advent of public key cryptography the term trapdoor has acquired a different meaning (see trapdoor function), and thus the term "backdoor" is now preferred, only after the term trapdoor went out of use. More generally, such security breaches were discussed at length in a RAND Corporation task force report published under ARPA sponsorship by J.P. Anderson and D.J. Edwards in 1970.[13]
A backdoor in a login system might take the form of a hard coded user and password combination which gives access to the system. An example of this sort of backdoor was used as a plot device in the 1983 film WarGames, in which the architect of the "WOPR" computer system had inserted a hardcoded password-less account which gave the user access to the system, and to undocumented parts of the system (in particular, a video game-like simulation mode and direct interaction with the artificial intelligence).
Although the number of backdoors in systems using proprietary software (software whose source code is not publicly available) is not widely credited, they are nevertheless frequently exposed. Programmers have even succeeded in secretly installing large amounts of benign code as Easter eggs in programs, although such cases may involve official forbearance, if not actual permission.
Covert backdoors sometimes masquerade as inadvertent defects (bugs) for reasons of plausible deniability. In some cases, these might begin life as an actual bug (inadvertent error), which, once discovered are then deliberately left unfixed and undisclosed, whether by a rogue employee for personal advantage, or with C-level executive awareness and oversight.
It is also possible for an entirely above-board corporation's technology base to be covertly and untraceably tainted by external agents (hackers), though this level of sophistication is thought to exist mainly at the level of nation state actors. For example, if a photomask obtained from a photomask supplier differs in a few gates from its photomask specification, a chip manufacturer would be hard-pressed to detect this if otherwise functionally silent; a covert rootkit running in the photomask etching equipment could enact this discrepancy unbeknown to the photomask manufacturer, either, and by such means, one backdoor potentially leads to another. (This hypothetical scenario is essentially a silicon version of the undetectable compiler backdoor, discussed below.)
In general terms, the long dependency-chains in the modern, highly specialized technological economy and innumerable human-elements process control-points make it difficult to conclusively pinpoint responsibility at such time as a covert backdoor becomes unveiled.
A sophisticated attempt to plant a backdoor in the Linux kernel, exposed in November 2003, added a small and subtle code change by subverting the revision control system.[14] In this case, a two-line change appeared to check root access permissions of a caller to the sys_wait4 function, but because it used assignment = instead of equality checking ==, it actually granted permissions to the system. This difference is easily overlooked, and could even be interpreted as an accidental typographical error, rather than an intentional attack.[15][16]
In January 2014, a backdoor was discovered in certain Samsung Android products, like the Galaxy devices. The Samsung proprietary Android versions are fitted with a backdoor that provides remote access to the data stored on the device. In particular, the Samsung Android software that is in charge of handling the communications with the modem, using the Samsung IPC protocol, implements a class of requests known as remote file server (RFS) commands, that allows the backdoor operator to perform via modem remote I/O operations on the device hard disk or other storage. As the modem is running Samsung proprietary Android software, it is likely that it offers over-the-air remote control that could then be used to issue the RFS commands and thus to access the file system on the device.[17]
A traditional backdoor is a symmetric backdoor: anyone that finds the backdoor can in turn use it. The notion of an asymmetric backdoor was introduced by Adam Young and Moti Yung in the Proceedings of Advances in Cryptology: Crypto '96. An asymmetric backdoor can only be used by the attacker who plants it, even if the full implementation of the backdoor becomes public (e.g., via publishing, being discovered and disclosed by reverse engineering, etc.). Also, it is computationally intractable to detect the presence of an asymmetric backdoor under black-box queries. This class of attacks have been termed kleptography; they can be carried out in software, hardware (for example, smartcards), or a combination of the two. The theory of asymmetric backdoors is part of a larger field now called cryptovirology. Notably, NSA inserted a kleptographic backdoor into the Dual EC DRBG standard.[4][20][21]
There exists an experimental asymmetric backdoor in RSA key generation. This OpenSSL RSA backdoor, designed by Young and Yung, utilizes a twisted pair of elliptic curves, and has been made available.[22]
A sophisticated form of black box backdoor is a compiler backdoor, where not only is a compiler subverted (to insert a backdoor in some other program, such as a login program), but it is further modified to detect when it is compiling itself and then inserts both the backdoor insertion code (targeting the other program) and the code-modifying self-compilation, like the mechanism through which retroviruses infect their host. This can be done by modifying the source code, and the resulting compromised compiler (object code) can compile the original (unmodified) source code and insert itself: the exploit has been boot-strapped. 2ff7e9595c
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