Exploits, Tools & Data Recovery · The Forensic Tool Landscape · Lesson 4 of 5

Controversies & Misuse

Study Signal's Cellebrite post, the Serbia spyware case and tool oversight.

When the tool is the target

In April 2021 Moxie Marlinspike, the creator of the encrypted messenger Signal, published a post on Signal's blog about the security of Cellebrite's own software. Cellebrite had announced a few months earlier that its tools supported Signal data. Signal's post turned the inspection around.

Marlinspike wrote, tongue in cheek, that a package of Cellebrite software and hardware had fallen off a truck in front of him. His main findings, as the post describes them:

• The software bundled copies of FFmpeg, a widely used open-source video library, built in 2012 and never updated, missing over a hundred security fixes released since.
• Standard exploit mitigations, the protections that make bugs harder to abuse, were missing.
• As a result, a specially formatted but ordinary-looking file inside any app on a phone could, once that phone was scanned, let an attacker run their own code on the examiner's computer.

The sharpest claim was about evidence. Signal wrote that such code could alter not only the current report but all previous and future reports from that machine, with no detectable timestamp changes or checksum failures. It hinted that future Signal versions would occasionally store files with no purpose in the app, a pointed suggestion that any phone might carry one. It offered to disclose the flaws to Cellebrite if Cellebrite disclosed the flaws it uses to get into phones, and questioned whether Cellebrite was licensed to include some Apple software files bundled with its tools.

About a week later, Vice reported that Cellebrite had released updates to address a recently identified security vulnerability, without saying whether it was the one Signal described. A Maryland defense lawyer, Ramon Rozas, asked for a new trial for a client convicted largely on Cellebrite evidence, arguing that the reported flaws called that evidence into question.

The post didn't show that any real report had been altered. What it showed was more basic: forensic tools process data that may be hostile, so they can be attacked like any other software, and labs need to keep them patched and tested.

Unlocked, then infected

In December 2024 Amnesty International published a report called A Digital Prison, about surveillance of journalists and activists in Serbia. Its Security Lab said Serbian police and intelligence officers had used Cellebrite's phone-unlocking products against them.

The lead case was independent journalist Slaviša Milanov. Amnesty says that in February 2024 he was taken to a police station on what appeared to be a routine drink-driving test, and his phone was held while he was questioned. Amnesty's analysis found his Android phone had been unlocked with a Cellebrite UFED product and then infected with NoviSpy, previously unknown Android spyware that can collect personal data and remotely switch on the microphone or camera. Amnesty attributed NoviSpy to Serbia's Security Information Agency (BIA) with high confidence and found similar evidence on an environmental activist's phone.

Amnesty also says a Cellebrite product was used to exploit a zero-day (a flaw unknown to the maker) to gain privileged access to an activist's phone. Amnesty identified the flaw with Google's security teams. It affected millions of Android devices with popular Qualcomm chipsets and was fixed in Qualcomm's October 2024 security bulletin. The report also described Pegasus spyware cases.

Cellebrite said its software doesn't install malware or perform real-time surveillance, and that it would investigate. In February 2025 it said it had found it appropriate to stop the use of its products by the relevant customers.

The case sharpens an old debate.

• For selling: police need these tools to investigate serious crimes such as child abuse and murder, and vendors say they vet customers and can cut off misuse.
• For caution: a tool sold for lawful searches can be used without a warrant, and vendors often learn of misuse only after researchers or journalists expose it.

That puts weight on oversight: warrants and court review, audit records of when tools are used, export rules, and independent forensic work by groups such as Amnesty and Citizen Lab.