Malicious PDF — malware analysis report

Static analysis result for SHA-256 b99c731a855879ac…

MALICIOUS

PDF

97.5 KB Created: 2021-06-27 15:37:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 25e03f9728f4754638b38293b966b27f SHA-1: 16b0f3dc92ee1ea74dd01f0fb2d1f423e71d3a16 SHA-256: b99c731a855879ac651147cfc5a21c6cafded164d2cb2da5ff7beb4f654bfa1b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a phishing or malware distribution attempt. It contains an embedded JavaScript stream and numerous external URIs, many of which point to compromised CMS uploads or disposable hosting, forming a link farm. The primary purpose appears to be redirecting users to external sites, likely to harvest credentials or deliver further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9802

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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://medvor.ru/uplcv?utm_term=meaning+of+physico
    • http://short-story.ru/upload/file/74341591427.pdf
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/160b770d11812f---76633626266.pdf
    • http://www.dnevi-sekretarjev.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1607219c7879d4---95540218055.pdf
    • http://dichvu12h.net/userfiles/file/93708042422.pdf
    • https://empylean.com/wp-content/plugins/super-forms/uploads/php/files/i9llruhapgubu72vupnr8ccftd/vufafajiwalawoxusibapuni.pdf
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16090f2429ebb2---85658710685.pdf
    • http://cleannshieldflorida.com/wp-content/plugins/super-forms/uploads/php/files/80765b32fb40cc987653ba089076e8da/16658364274.pdf
    • http://reelproductionshd.com/userfiles/file/60607835565.pdf
    • http://staractivecollection.com/resimler/site/files/84567525066.pdf
    • http://caphegiabao.com/upload/fck/file/tobovijesadupunebuve.pdf
    • http://eros-arena-reutlingen.de/eros/userfiles/file/28311869350.pdf
    • https://handinhand-daycare.com/ckfinder/userfiles/files/zasubuvone.pdf
    • https://www.projectorrentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609eb2c31d7f5---67986244878.pdf
    • http://uci.ir/userfiles/file/46269636727.pdf
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1609b2637ac008---vowuv.pdf
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/vn9113sg410t1qjrtm5v3so0k3/tipudobofu.pdf
    • http://marymo.ru/uploads/files/fepemanosegafemifu.pdf
    • http://pansophers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cad97210ad---47306788325.pdf
    • http://snookerfootball.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1609ea0853c98d---74782131865.pdf
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160727f540a298---tukaxorusagefunenumen.pdf
    • https://najlepsze-w-polsce.pl/uploads/gemuraposur.pdf
    • http://maduraicaterers.com/app/webroot/js/ckfinder/userfiles/files/wanexudi.pdf
    • http://sun-tes.ru/files/file/bafozul.pdf
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16093aa560ccfe---86662256213.pdf
    • https://sckstone.com/wp-content/plugins/super-forms/uploads/php/files/44235709abe3a2db212389814058761e/zetoboniruporoj.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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_006_off000158d0.bin
d9f5e66163d907df9b2c2f031b8906ab183602eda4757f3e8ef428a9cf922d60
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x158D0 18328 bytes
font_00_sfnt_off0000e072.bin
71ef7d8a314ce169737cd727f220a62d100ea0627d446c212edd685bef9f7052
pdf-font-stream PDF embedded font (sfnt) at offset 0xE072 10620 bytes
font_01_sfnt_off0000f8a7.bin
a8161c2f5ba9235eb51b4fcc43b6bb219725019365cb8d38f9ec25dfe5ce54ff
pdf-font-stream PDF embedded font (sfnt) at offset 0xF8A7 3464 bytes
font_02_sfnt_off00010626.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10626 16792 bytes
font_03_sfnt_off00011e38.bin
d4a7dad82d1d279fe64717dde6a89c1b29f03c4cc84180c5abc570814bbc8bb8
pdf-font-stream PDF embedded font (sfnt) at offset 0x11E38 23740 bytes