Malicious PDF — malware analysis report

Static analysis result for SHA-256 83661ebd272e1bd5…

MALICIOUS

PDF

82.5 KB Created: 2021-09-23 01:23:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 840763adab1606555f44cf2262f8e3f3 SHA-1: bb381caaed9d8dbecdda344ad2db164a14d3ea2d SHA-256: 83661ebd272e1bd5ebeedab9a33d2a6cd2c45a9ed22a982eaf8c04a46bd7b5b7
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

This PDF document was flagged by a machine learning classifier and ClamAV as malicious, indicating it is likely a phishing or trojan delivery mechanism. The presence of numerous external URIs, many hosted on disposable domains or compromised WordPress sites, suggests a link farm designed to redirect users to malicious content. The 'Macro/content-enable lure' heuristic indicates the document likely instructs the user to enable content, a common tactic for malware droppers.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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 https://chcial.ru/uplcv?utm_term=find+my+ad+blocker
    • http://mu-rrrc.com/userfiles/file/vupiwawumiredokefa.pdf
    • http://rovitek.com/userfiles/file/50723660234.pdf
    • https://permargi.com/files/galeria/files/96727123848.pdf
    • http://hanahana.vn/media/ftp/file/tofimesatakukosufezelij.pdf
    • https://bistakalikotenetwork.com/userfiles/file/wuwalinajoxojebufogukuw.pdf
    • http://toanthinh.vn/webroot/img/files/zoboxigigobagoti.pdf
    • https://chiuman-hk.com/images/file/34938589833.pdf
    • http://eco-versute.com/app/webroot/ckfinder/userfiles/files/24648396447.pdf
    • https://wangwangcamp.com/uploads/files/202109011559008740.pdf
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/161371b8b78597---1929346161.pdf
    • https://bursaceviritercume.com/wp-content/plugins/formcraft/file-upload/server/content/files/161477855a5cf5---36796383467.pdf
    • http://gardensyellowcab.com/admin/images/file/nulufujovifuterasunu.pdf
    • http://meyergarden.com/ckfinder/userfiles/files/sizasogadijeni.pdf
    • http://nyitotthaz.hu/userfiles/files/45270017494.pdf
    • https://mygoaltv.com/ipp/images/uploads/files/bibonasagaj.pdf
    • http://antwerp-reefer-tournament.be/argt/files/78332032909.pdf
    • http://sjccgy.com/userfiles/file/wisujabakejudatirepivev.pdf
    • http://phdpecs.hu/userfiles/files/bipivi.pdf
    • http://nriloan.jctoursandtravels.in/files/dasagoxemipokevimese.pdf
    • https://messianic.live/wp-content/plugins/super-forms/uploads/php/files/8d18e0131cd6be6553ac614a779944e5/6362222178.pdf
    • https://thaiahpa.com/flash/files/37004558734.pdf
    • https://tese.in/ckfinder/userfiles/files/raxuwesikil.pdf
    • http://champaigncursillo.com/userfiles/file/29187428830.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_off0000defa.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDEFA 16792 bytes
font_01_sfnt_off0000f70c.bin
01e7d25d840534b5eca03caa0afee4b71ec4b587498201e9f24cd6c93edc8fc2		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF70C 17500 bytes
font_02_sfnt_off00012445.bin
32e126191531a59e889db05ba6ea77b1feb4bd6abeeb1d62f1d7ab662fb88454		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12445 10588 bytes

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