Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a28861b8fe93049…

MALICIOUS

PDF

85.0 KB Created: 2021-07-06 14:35:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e70eff8e3667dc4ddb207bc80d5235a2 SHA-1: 71f2141900a7caaf39096ec65e9d9eb67c9c5409 SHA-256: 6a28861b8fe9304921798b718aa3da705a73d4b9b4a1be3bfa4b71e696f7772e
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to compromised WordPress sites, suggesting a link farm designed to direct users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the URL analysis and heuristic firings are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 6

  • 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.
  • 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://smidgel.ru/uplcv?utm_term=inner+thigh+cramps
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/urtt5d7i5ti0svgrpqihhbu6i5/79902191217.pdf
    • https://vallejardin.com/wp-content/plugins/super-forms/uploads/php/files/81e098b7471e6e6dd33171fe33b6df6d/rudexisekijajedogu.pdf
    • https://maugli24.ru/wp-content/plugins/super-forms/uploads/php/files/b8ccee4a530f71c1355778fa4ef124e8/66050187016.pdf
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a370552c127---lekenemori.pdf
    • https://baptistfriends.org/media/91232859107.pdf
    • https://butterfly-propertymanagement.com/userfiles/file/46261842217.pdf
    • http://hersheyhigh1981.com/clients/37302/File/tafitefisovureworejaz.pdf
    • http://ukicda.com/admin/fckeditor_upfiles/file/2021070619202580554.pdf
    • https://numberonerevolution.it/file/81790538476.pdf
    • https://alihuata.com/userfiles/file/1108737757.pdf
    • http://pvsystexperts.com/wp-content/plugins/super-forms/uploads/php/files/hhl7p9e2i7m5v5k80gdn929ne2/11916241389.pdf
    • https://abugfreemind.com/userfiles/file/90983713279.pdf
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083e12351350---duvivem.pdf
    • https://fonixkoncert.hu/upload/file/fidepajijokemusufo.pdf
    • https://www.charroninc.com/wp-content/plugins/super-forms/uploads/php/files/7fb6a7c6b0fe6b14402430cbcd506ada/tarijebafexadudavote.pdf
    • http://pantipplaza.com/userfiles/file/25860448196.pdf
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0ea32ac02f---xunuxidazuri.pdf
    • http://nakatka.com/files/file/49181213574.pdf
    • https://islandsvefir.is/wp-content/plugins/super-forms/uploads/php/files/7ad16ao0745ifqf0c80es2kl1s/4337568287.pdf
    • http://njf724.com/basefile/janatalnajafcom/files/kejimapabirafexajeg.pdf
    • https://mednet.mk/public_html/upload/userfiles/file/wesikojukobanunano.pdf
    • http://www.guaitoli.eng.br/wp-content/plugins/formcraft/file-upload/server/content/files/16092fa35896b2---29432102412.pdf
    • http://totaleclipsenv.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072929a34d12---girolujowibugiwizufawogew.pdf
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/6609614703d599a921d80f17d5b4ea5f/votor.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_off0000ed33.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xED33 16792 bytes
font_01_sfnt_off00010545.bin
cc13f1678fb3341e54d490143906e64afcb21c32f0522b4ede72beba3d606b7d
pdf-font-stream PDF embedded font (sfnt) at offset 0x10545 16136 bytes
font_02_sfnt_off00012ee8.bin
bf64be7b010d6fea3bee33463cd48856baed6a36783b42c48cadc46b42c189d7
pdf-font-stream PDF embedded font (sfnt) at offset 0x12EE8 10604 bytes