Office MACROS PERIL! Age-old VBScript tactic is BACK in biz attack

'Office macro exploits only cool thing Visual Basic used for,' quips securobod

The dangers of allowing Office macros have been underlined by a newly discovered attack against European and Israeli companies.

Malicious Office macros were used as the launchpad of the so-called RocketKitten attacks presented at this year's Chaos Communication Congress hacking conference (stream here, relevant material starts around 20 minutes in). The technique is nothing new and still effective - even though it has been around for years and is straightforward to block.

Visual Basic for Applications (VBA) is one of the easiest methods to deliver malware nasties: simply by dropping malicious code into an Office doc as a macro and attaching to an email. The victim would be lured by a plausible pretext into opening an Office file attachment delivered to them by email.

“It’ll often have ‘lure’ content that looks plausible, convincing the user to click the 'enable macros' alert, the macro runs, then we have lovely reverse shell and back door on their desktop,” explained Ken Munro of security consultancy Pen Test Partners. “This is usually easier than sending executables by email, as those are blocked by Outlook and/or may require local admin rights to install.”

The fix is easy, but hardly any organisations do it: simply block macros in Group Policy.

“Some departments need macros for spreadsheet and other operations, but at the very least restrict macro use to only those who explicitly need it,” Munro told El Reg. “Give special training on phishing attacks to those who do have macros enabled, and ensure they are particularly careful with Office files from external sources.”

“It’s often the finance department that relies on macros - ah yes, the department that has access to the company bank accounts and makes the ideal target for banking credential theft. The average user simply doesn't need them, so this isn’t going to cause much inconvenience,” he added.

Other mitigation techniques involve digitally signing approved macros after establishes policies that mean only signed macros will run.

The issue goes beyond the recent VBScript vulnerability, patched by Microsoft in early December. “There’s a far broader issue around VB and Office macros that seems overlooked by most,” Munro concluded. “It isn't new; everyone in the pen test space knows about it, but few IT security people in end user land seem to appreciate its significance.

“Office macro exploits are just about the only cool thing that Visual Basic gets used for any more,” he added.

Munro has put together a blog post - featuring tests on proof of concept malicious code - explaining the issue in greater depth here. ®

Other stories you might like

  • Venezuelan cardiologist charged with designing and selling ransomware
    If his surgery was as bad as his opsec, this chap has caused a lot of trouble

    The US Attorney’s Office has charged a 55-year-old cardiologist with creating and selling ransomware and profiting from revenue-share agreements with criminals who deployed his product.

    A complaint [PDF] filed on May 16th in the US District Court, Eastern District of New York, alleges that Moises Luis Zagala Gonzalez – aka “Nosophoros,” “Aesculapius” and “Nebuchadnezzar” – created a ransomware builder known as “Thanos”, and ransomware named “Jigsaw v. 2”.

    The self-taught coder and qualified cardiologist advertised the ransomware in dark corners of the web, then licensed it ransomware to crooks for either $500 or $800 a month. He also ran an affiliate network that offered the chance to run Thanos to build custom ransomware, in return for a share of profits.

    Continue reading
  • China reveals its top five sources of online fraud
    'Brushing' tops the list, as quantity of forbidden content continue to rise

    China’s Ministry of Public Security has revealed the five most prevalent types of fraud perpetrated online or by phone.

    The e-commerce scam known as “brushing” topped the list and accounted for around a third of all internet fraud activity in China. Brushing sees victims lured into making payment for goods that may not be delivered, or are only delivered after buyers are asked to perform several other online tasks that may include downloading dodgy apps and/or establishing e-commerce profiles. Victims can find themselves being asked to pay more than the original price for goods, or denied promised rebates.

    Brushing has also seen e-commerce providers send victims small items they never ordered, using profiles victims did not create or control. Dodgy vendors use that tactic to then write themselves glowing product reviews that increase their visibility on marketplace platforms.

    Continue reading
  • Oracle really does owe HPE $3b after Supreme Court snub
    Appeal petition as doomed as the Itanic chips at the heart of decade-long drama

    The US Supreme Court on Monday declined to hear Oracle's appeal to overturn a ruling ordering the IT giant to pay $3 billion in damages for violating a decades-old contract agreement.

    In June 2011, back when HPE had not yet split from HP, the biz sued Oracle for refusing to add Itanium support to its database software. HP alleged Big Red had violated a contract agreement by not doing so, though Oracle claimed it explicitly refused requests to support Intel's Itanium processors at the time.

    A lengthy legal battle ensued. Oracle was ordered to cough up $3 billion in damages in a jury trial, and appealed the decision all the way to the highest judges in America. Now, the Supreme Court has declined its petition.

    Continue reading

Biting the hand that feeds IT © 1998–2022