Entries Tagged "forensics"

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Tracking Down a Suspect through Cell Phone Records

Interesting forensics in connection with a serial killer arrest:

Investigators went through phone records collected from both midtown Manhattan and the Massapequa Park area of Long Island—two areas connected to a “burner phone” they had tied to the killings. (In court, prosecutors later said the burner phone was identified via an email account used to “solicit and arrange for sexual activity.” The victims had all been Craigslist escorts, according to officials.)

They then narrowed records collected by cell towers to thousands, then to hundreds, and finally down to a handful of people who could match a suspect in the killings.

From there, authorities focused on people who lived in the area of the cell tower and also matched a physical description given by a witness who had seen the suspected killer.

In that narrowed pool, they searched for a connection to a green pickup truck that a witness had seen the suspect driving, the sources said.

Investigators eventually landed on Heuermann, who they say matched a witness’ physical description, lived close to the Long Island cell site and worked near the New York City cell sites that captured the other calls.

They also learned he had often driven a green pickup truck, registered to his brother, officials said. But they needed more than just circumstantial evidence.

Investigators were able to obtain DNA from an immediate family member and send it to a specialized lab, sources said. According to the lab report, Heuermann’s family member was shown to be related to a person who left DNA on a burlap sack containing one of the buried victims.

There’s nothing groundbreaking here; it’s casting a wide net with cell phone geolocation data and then winnowing it down using other evidence and investigative techniques. And right now, those are expensive and time consuming, so only used in major crimes like murder (or, in this case, murders).

What’s interesting to think about is what happens when this kind of thing becomes cheap and easy: when it can all be done through easily accessible databases, or even when an AI can do the sorting and make the inferences automatically. Cheaper digital forensics means more digital forensics, and we’ll start seeing this kind of thing for even routine crimes. That’s going to change things.

Posted on July 17, 2023 at 7:13 AM • View Comments

Typing Incriminating Evidence in the Memo Field

Don’t do it:

Recently, the manager of the Harvard Med School morgue was accused of stealing and selling human body parts. Cedric Lodge and his wife Denise were among a half-dozen people arrested for some pretty grotesque crimes. This part is also at least a little bit funny though:

Over a three-year period, Taylor appeared to pay Denise Lodge more than $37,000 for human remains. One payment, for $1,000 included the memo “head number 7.” Another, for $200, read “braiiiiiins.”

It’s so easy to think that you won’t get caught.

Posted on June 27, 2023 at 4:36 PM • View Comments

Identifying the Idaho Killer

The New York Times has a long article on the investigative techniques used to identify the person who stabbed and killed four University of Idaho students.

Pay attention to the techniques:

The case has shown the degree to which law enforcement investigators have come to rely on the digital footprints that ordinary Americans leave in nearly every facet of their lives. Online shopping, car sales, carrying a cellphone, drives along city streets and amateur genealogy all played roles in an investigation that was solved, in the end, as much through technology as traditional sleuthing.

[…]

At that point, investigators decided to try genetic genealogy, a method that until now has been used primarily to solve cold cases, not active murder investigations. Among the growing number of genealogy websites that help people trace their ancestors and relatives via their own DNA, some allow users to select an option that permits law enforcement to compare crime scene DNA samples against the websites’ data.

A distant cousin who has opted into the system can help investigators building a family tree from crime scene DNA to triangulate and identify a potential perpetrator of a crime.

[…]

On Dec. 23, investigators sought and received Mr. Kohberger’s cellphone records. The results added more to their suspicions: His phone was moving around in the early morning hours of Nov. 13, but was disconnected from cell networks ­- perhaps turned off—in the two hours around when the killings occurred.

Posted on June 13, 2023 at 7:03 AM • View Comments

Operation Triangulation: Zero-Click iPhone Malware

Kaspersky is reporting a zero-click iOS exploit in the wild:

Mobile device backups contain a partial copy of the filesystem, including some of the user data and service databases. The timestamps of the files, folders and the database records allow to roughly reconstruct the events happening to the device. The mvt-ios utility produces a sorted timeline of events into a file called “timeline.csv,” similar to a super-timeline used by conventional digital forensic tools.

Using this timeline, we were able to identify specific artifacts that indicate the compromise. This allowed to move the research forward, and to reconstruct the general infection sequence:

  • The target iOS device receives a message via the iMessage service, with an attachment containing an exploit.
  • Without any user interaction, the message triggers a vulnerability that leads to code execution.
  • The code within the exploit downloads several subsequent stages from the C&C server, that include additional exploits for privilege escalation.
  • After successful exploitation, a final payload is downloaded from the C&C server, that is a fully-featured APT platform.
  • The initial message and the exploit in the attachment is deleted

The malicious toolset does not support persistence, most likely due to the limitations of the OS. The timelines of multiple devices indicate that they may be reinfected after rebooting. The oldest traces of infection that we discovered happened in 2019. As of the time of writing in June 2023, the attack is ongoing, and the most recent version of the devices successfully targeted is iOS 15.7.

No attribution as of yet.

Posted on June 9, 2023 at 7:12 AM • View Comments

The Insecurity of Photo Cropping

The Intercept has a long article on the insecurity of photo cropping:

One of the hazards lies in the fact that, for some of the programs, downstream crop reversals are possible for viewers or readers of the document, not just the file’s creators or editors. Official instruction manuals, help pages, and promotional materials may mention that cropping is reversible, but this documentation at times fails to note that these operations are reversible by any viewers of a given image or document.

[…]

Uncropped versions of images can be preserved not just in Office apps, but also in a file’s own metadata. A photograph taken with a modern digital camera contains all types of metadata. Many image files record text-based metadata such as the camera make and model or the GPS coordinates at which the image was captured. Some photos also include binary data such as a thumbnail version of the original photo that may persist in the file’s metadata even after the photo has been edited in an image editor.

Posted on February 21, 2023 at 7:14 AM • View Comments

Surveillance of the Internet Backbone

Vice has an article about how data brokers sell access to the Internet backbone. This is netflow data. It’s useful for cybersecurity forensics, but can also be used for things like tracing VPN activity.

At a high level, netflow data creates a picture of traffic flow and volume across a network. It can show which server communicated with another, information that may ordinarily only be available to the server owner or the ISP carrying the traffic. Crucially, this data can be used for, among other things, tracking traffic through virtual private networks, which are used to mask where someone is connecting to a server from, and by extension, their approximate physical location.

In the hands of some governments, that could be dangerous.

Posted on August 25, 2021 at 10:13 AM • View Comments

Risks of Evidentiary Software

Over at Lawfare, Susan Landau has an excellent essay on the risks posed by software used to collect evidence (a Breathalyzer is probably the most obvious example).

Bugs and vulnerabilities can lead to inaccurate evidence, but the proprietary nature of software makes it hard for defendants to examine it.

The software engineers proposed a three-part test. First, the court should have access to the “Known Error Log,” which should be part of any professionally developed software project. Next the court should consider whether the evidence being presented could be materially affected by a software error. Ladkin and his co-authors noted that a chain of emails back and forth are unlikely to have such an error, but the time that a software tool logs when an application was used could easily be incorrect. Finally, the reliability experts recommended seeing whether the code adheres to an industry standard used in an non-computerized version of the task (e.g., bookkeepers always record every transaction, and thus so should bookkeeping software).

[…]

Inanimate objects have long served as evidence in courts of law: the door handle with a fingerprint, the glove found at a murder scene, the Breathalyzer result that shows a blood alcohol level three times the legal limit. But the last of those examples is substantively different from the other two. Data from a Breathalyzer is not the physical entity itself, but rather a software calculation of the level of alcohol in the breath of a potentially drunk driver. As long as the breath sample has been preserved, one can always go back and retest it on a different device.

What happens if the software makes an error and there is no sample to check or if the software itself produces the evidence? At the time of our writing the article on the use of software as evidence, there was no overriding requirement that law enforcement provide a defendant with the code so that they might examine it themselves.

[…]

Given the high rate of bugs in complex software systems, my colleagues and I concluded that when computer programs produce the evidence, courts cannot assume that the evidentiary software is reliable. Instead the prosecution must make the code available for an “adversarial audit” by the defendant’s experts. And to avoid problems in which the government doesn’t have the code, government procurement contracts must include delivery of source code­—code that is more-or-less readable by people—­for every version of the code or device.

Posted on June 29, 2021 at 9:12 AM • View Comments

More SolarWinds News

Microsoft analyzed details of the SolarWinds attack:

Microsoft and FireEye only detected the Sunburst or Solorigate malware in December, but Crowdstrike reported this month that another related piece of malware, Sunspot, was deployed in September 2019, at the time hackers breached SolarWinds’ internal network. Other related malware includes Teardrop aka Raindrop.

Details are in the Microsoft blog:

We have published our in-depth analysis of the Solorigate backdoor malware (also referred to as SUNBURST by FireEye), the compromised DLL that was deployed on networks as part of SolarWinds products, that allowed attackers to gain backdoor access to affected devices. We have also detailed the hands-on-keyboard techniques that attackers employed on compromised endpoints using a powerful second-stage payload, one of several custom Cobalt Strike loaders, including the loader dubbed TEARDROP by FireEye and a variant named Raindrop by Symantec.

One missing link in the complex Solorigate attack chain is the handover from the Solorigate DLL backdoor to the Cobalt Strike loader. Our investigations show that the attackers went out of their way to ensure that these two components are separated as much as possible to evade detection. This blog provides details about this handover based on a limited number of cases where this process occurred. To uncover these cases, we used the powerful, cross-domain optics of Microsoft 365 Defender to gain visibility across the entire attack chain in one complete and consolidated view.

This is all important, because MalwareBytes was penetrated through Office 365, and not SolarWinds. New estimates are that 30% of the SolarWinds victims didn’t use SolarWinds:

Many of the attacks gained initial footholds by password spraying to compromise individual email accounts at targeted organizations. Once the attackers had that initial foothold, they used a variety of complex privilege escalation and authentication attacks to exploit flaws in Microsoft’s cloud services. Another of the Advanced Persistent Threat (APT)’s targets, security firm CrowdStrike, said the attacker tried unsuccessfully to read its email by leveraging a compromised account of a Microsoft reseller the firm had worked with.

On attribution: Earlier this month, the US government has stated the attack is “likely Russian in origin.” This echos what then Secretary of State Mike Pompeo said in December, and the Washington Post‘s reporting (both from December). (The New York Times has repeated this attribution—a good article that also discusses the magnitude of the attack.) More evidence comes from code forensics, which links it to Turla, another Russian threat actor.

And lastly, a long ProPublica story on an unused piece of government-developed tech that might have caught the supply-chain attack much earlier:

The in-toto system requires software vendors to map out their process for assembling computer code that will be sent to customers, and it records what’s done at each step along the way. It then verifies electronically that no hacker has inserted something in between steps. Immediately before installation, a pre-installed tool automatically runs a final check to make sure that what the customer received matches the final product the software vendor generated for delivery, confirming that it wasn’t tampered with in transit.

I don’t want to hype this defense too much without knowing a lot more, but I like the approach of verifying the software build process.

Posted on February 3, 2021 at 6:10 AM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.