Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Attacks/Breaches

3/11/2008
08:20 AM
Connect Directly
Google+
Twitter
RSS
E-Mail
50%
50%

FTP Hacking on the Rise

First it was stolen FTP server admin privileges. Now it's spam messages with bot-infected FTP links

The File Transfer Protocol (FTP) has attracted renewed interest lately, but not in a good way: The bad guys are now using the ‘70s disco-era file transfer technology to serve up bot malware, and even as a backdoor into some enterprises that neglect to lock down their FTP servers.

Researchers at F-Secure have spotted a new wave of exploits that use FTP -- rather than a malicious URL, or the conspicuous email attachment -- to deliver their malware payloads. “As SMTP and HTTP are much better filtered for malware, FTP might be the best transport protocol for a virus writer,” says Mikko Hypponen, chief research officer for F-Secure. “We've just started to observe this phenomenon -- it's not widespread yet, but likely to increase.”

Last month, researchers at Finjan stumbled onto a cache of stolen FTP server administrative credentials that put nearly 9,000 FTP servers at some major global companies at risk, demonstrating just how widespread the old-school FTP remains at many organizations. Cybercriminals were selling a new crimeware package that would automatically infect those servers, some of which were from the world's top 100 domains. (See Stolen FTP Credentials Offered for Sale: Major Firms at Risk.)

F-Secure’s team last week discovered malicious Hallmark greeting card spam messages aimed at recruiting bots. The messages’ links to “view” the greeting instead take the victims to a bot-infected machine serving as an FTP site. The code it downloads is actually a variant of the Zapchast mIRC-bot, according to F-Secure. Instead of receiving the greeting, the user becomes a bot.

So why this retro-borne attack, especially when use of FTP is on the wane? FTP today is often a forgotten or unknown hole in the security of an organization -- not many enterprises bother to monitor it. And for bot herders, it’s just another means of moving malware.

“FTP is more popular than anyone knows -- a lot of people still send FTP stuff back and forth because it’s easy to do,” says Taher Elgamal, CTO of Tumbleweed Communications, which sells secure FTP software. And from the bad guy’s perspective, FTP is less likely to be blocked than an instant message, he says. “FTP is sort of left alone because it’s supposed to be an old thing no one cares about. But it’s an effective protocol for transferring large files... That’s why we’re seeing this [attack] phenomenon.”

Elgamal says the bad guys can hop on Port 80 and ship FTP through that port, for example, and a firewall wouldn’t block the file transfer. Some Internet gateways scan for FTP traffic, such as F-Secure’s Internet Gatekeeper, which does so by default. But many organizations just don’t bother scanning for FTP traffic at all either because they don’t consider it a risk or they don’t realize it’s being used, security experts say.

Still, the FTP-borne attack obviously won’t ever be as big as an HTTP-borne one. “Most companies wouldn't set up a new FTP site any more -- it's so old school. [But] the [FTP] sites that are out there are old and often forgotten about and poorly protected,” F-Secure’s Hypponen says.

Have a comment on this story? Please click "Discuss" below. If you'd like to contact Dark Reading's editors directly, send us a message.

  • F-Secure Corp.
  • Finjan Software Inc.
  • Tumbleweed Communications Corp. (Nasdaq: TMWD)

    Kelly Jackson Higgins is the Executive Editor of Dark Reading. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise ... View Full Bio

    Comment  | 
    Print  | 
    More Insights
  • Comments
    Newest First  |  Oldest First  |  Threaded View
    COVID-19: Latest Security News & Commentary
    Dark Reading Staff 9/25/2020
    Hacking Yourself: Marie Moe and Pacemaker Security
    Gary McGraw Ph.D., Co-founder Berryville Institute of Machine Learning,  9/21/2020
    Startup Aims to Map and Track All the IT and Security Things
    Kelly Jackson Higgins, Executive Editor at Dark Reading,  9/22/2020
    Register for Dark Reading Newsletters
    White Papers
    Video
    Cartoon
    Current Issue
    Special Report: Computing's New Normal
    This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
    Flash Poll
    How IT Security Organizations are Attacking the Cybersecurity Problem
    How IT Security Organizations are Attacking the Cybersecurity Problem
    The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
    Twitter Feed
    Dark Reading - Bug Report
    Bug Report
    Enterprise Vulnerabilities
    From DHS/US-CERT's National Vulnerability Database
    CVE-2020-15208
    PUBLISHED: 2020-09-25
    In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, when determining the common dimension size of two tensors, TFLite uses a `DCHECK` which is no-op outside of debug compilation modes. Since the function always returns the dimension of the first tensor, malicious attackers can ...
    CVE-2020-15209
    PUBLISHED: 2020-09-25
    In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, a crafted TFLite model can force a node to have as input a tensor backed by a `nullptr` buffer. This can be achieved by changing a buffer index in the flatbuffer serialization to convert a read-only tensor to a read-write one....
    CVE-2020-15210
    PUBLISHED: 2020-09-25
    In tensorflow-lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, if a TFLite saved model uses the same tensor as both input and output of an operator, then, depending on the operator, we can observe a segmentation fault or just memory corruption. We have patched the issue in d58c96946b and ...
    CVE-2020-15211
    PUBLISHED: 2020-09-25
    In TensorFlow Lite before versions 1.15.4, 2.0.3, 2.1.2, 2.2.1 and 2.3.1, saved models in the flatbuffer format use a double indexing scheme: a model has a set of subgraphs, each subgraph has a set of operators and each operator has a set of input/output tensors. The flatbuffer format uses indices f...
    CVE-2020-15212
    PUBLISHED: 2020-09-25
    In TensorFlow Lite before versions 2.2.1 and 2.3.1, models using segment sum can trigger writes outside of bounds of heap allocated buffers by inserting negative elements in the segment ids tensor. Users having access to `segment_ids_data` can alter `output_index` and then write to outside of `outpu...