Malicious PDF — malware analysis report

Static analysis result for SHA-256 a71cc23f87ba4ed3…

MALICIOUS

PDF

94.9 KB Created: 2021-07-02 15:45:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4a751acd251fc5dd8f18ac3acc71f9a6 SHA-1: d14b6981a1daf88e9ed0375f1c8b91b3c4649e28 SHA-256: a71cc23f87ba4ed3324d729489f907e5a23f77a668eada37912141b6be4fb8dc
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file containing embedded JavaScript and a large number of external URIs. Several heuristics indicate that the PDF is a link farm hosted on compromised WordPress sites, with URLs pointing to various domains. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 7

  • 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.
  • 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://nomylo.ru/uplcv?utm_term=case+interview+sample+questions+and+answers
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1609ebecf43999---96855322754.pdf
    • http://szalkasszorutacskok.hu/app/webroot/files/content/files/rixidedasorososajuxo.pdf
    • http://www.peplex.it/wp-content/plugins/formcraft/file-upload/server/content/files/160b7970d2502c---mugebovomipaguralukijozo.pdf
    • https://alenakovalchuk.ru/wp-content/plugins/super-forms/uploads/php/files/a11dbb44395c210418ed1e0230472872/78019886880.pdf
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/160774be17208e---64131337999.pdf
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160791217ce916---46168737690.pdf
    • http://ecbpolska.pl/wp-content/plugins/super-forms/uploads/php/files/682750466b6f243f2d505367470e2c06/72140888306.pdf
    • https://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/cb4d5da0b0a29a4f8201b42512c7c5c9/barozuwusilalizovuguz.pdf
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bc3045de666---vifedenuniziwekose.pdf
    • https://www.enterpriselighting.com/wp-content/plugins/super-forms/uploads/php/files/ad25dcd75ae38e77c3c79779fccef0a3/55321170375.pdf
    • https://cor.org.ar/wp-content/plugins/super-forms/uploads/php/files/5cenbetc6v3nobtnr90a7ispmt/vokakeveliliregiguxijavi.pdf
    • http://bpsstudio.hu/uploads/bebetenoxizoxajawosoro.pdf
    • http://www.lightingandhvacexpo.com/wp-content/plugins/super-forms/uploads/php/files/36891b6269ca8fa61df76a2dc034ae8c/rekirizovafol.pdf
    • http://plusk-car.com/js/upload/files/97766253528.pdf
    • http://www.toptehnik.si/images/vebabu.pdf
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075d9280b3a1---mixowuduzonarujolipavil.pdf
    • https://www.hadlowsecurityshutters.com/wp-content/plugins/super-forms/uploads/php/files/99edf2eace78803e739df1c0d9d40a6d/xekulu.pdf
    • https://asigurareingermania.ro/wp-content/plugins/super-forms/uploads/php/files/9lmvaol6q8drs7k0c35p2i4p9v/77126754736.pdf
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16085f611af004---95326347303.pdf
    • http://www.scsi.coop/wp-content/plugins/super-forms/uploads/php/files/6998a18eacd394c0e5f3cb65a1292b1d/55246048241.pdf
    • http://accomplishtheimpossible.com/userfiles_ati/file/4827918363.pdf
    • http://canyonoaksmtg.com/~duckdi5/canyonoaksmtg.com/content/file/96442773982.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_off00010dc1.bin
f2d765a1ab358578537dd6ef5b0dcb2ae986bcdfe5465f0a39d0beca65a29344
pdf-font-stream PDF embedded font (sfnt) at offset 0x10DC1 18000 bytes
font_01_sfnt_off00013ce0.bin
a28a26eecacc0b495b95aa45d423b66c93a79d8b982736cee484f254230e54fb
pdf-font-stream PDF embedded font (sfnt) at offset 0x13CE0 10980 bytes
font_02_sfnt_off00015630.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x15630 16792 bytes