Malicious PDF — malware analysis report

Static analysis result for SHA-256 81631b9b29b887f5…

MALICIOUS

PDF

83.1 KB Created: 2021-09-18 19:14:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9f8713d044c2b39754268550f2f424d7 SHA-1: 60b3ea4ffefeaaffe96b1d0b40bac9e6999bffda SHA-256: 81631b9b29b887f56da5c50fe68bf3ff9ac1a023c748d6b44a883c93d2082ace
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains multiple heuristics indicating it is a link farm and a phishing lure, including a fake download button and a callback lure. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated, but the presence of multiple links to potentially compromised or disposable hosting services points towards a phishing or scam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614052b009e76---panidoburixap.pdf
    • https://beautifulhairstore.com/upload/files/rumekebiroz.pdf
    • http://ferien-in-zahren.de/images/file/domofupod.pdf
    • https://esprimagroup.com/userfiles/file/12417627777.pdf
    • http://sdtrafficticketlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/50278206897.pdf
    • http://rgn2u.com/userfiles/files/botuwegofoxaroluvupigimob.pdf
    • http://duhochoangthanh.com/upload/files/dogizizudakovujasagutun.pdf
    • http://upnbkk.com/file_media/file_image/file/poluzired.pdf
    • http://havefuntogether.com/image/upload/File/10977226575.pdf
    • http://skkl.cn/filespath/files/20210917004423.pdf
    • https://beeshark.ro/app/webroot/files/userfiles/files/duvater.pdf
    • http://adhdesign.de/userContent/files/20210913121940-donumomulavubatokubuzed.pdf
    • https://cupanghitam.com/contents/files/nozufawe.pdf
    • https://2b3la571ga-70p.com/contents/files/37488808949.pdf
    • https://ekinyalitim.com/depo/sayfaresim/file/69507135634.pdf
    • http://clinivetmadonnadirosa.eu/userfiles/files/burexenawosano.pdf
    • http://ajtoablakcentrum.com/_user/file/50776746506.pdf
    • https://jancsoalapitvany.hu/ckfinder/userfiles/files/potidaxamedigusuze.pdf
    • https://gencerenerji.com/resimler/files/11446999915.pdf
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/c9407e182ea512720c2833d0fc45344a/jesoxodajofunuj.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143c4f4355a8---gatibagixujiwetiw.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=apowermirror+vip+for+pc+download
    • http://cluster006.ovh.net/~greeters/be/ckfinder/userfiles/files/rigulikawapuw.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e15a.bin
1848978d95fe8d98e9f6fbc16909a87386a3d941b78053c2464ab9bb15afeeb6
pdf-font-stream PDF embedded font (sfnt) at offset 0xE15A 10648 bytes
font_01_sfnt_off0000f9bf.bin
be50e8654c1feda390f227b22b9e56a887c6035d14a1eda876afffa1f51d5dbe
pdf-font-stream PDF embedded font (sfnt) at offset 0xF9BF 17312 bytes
font_02_sfnt_off000126a8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x126A8 16792 bytes