Malicious PDF — malware analysis report

Static analysis result for SHA-256 81c45391fb757df4…

MALICIOUS

PDF

104.3 KB Created: 2021-07-03 16:43:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c087395fa3952aa68ca8979c1973456d SHA-1: b84d1644876f429e0451d093605a8e09234f0533 SHA-256: 81c45391fb757df418c113129e380d07f76963e075323b921809f0eb58dd2772
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a link farm with numerous URLs pointing to compromised hosting and disposable domains, a common tactic for phishing or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body is heavily obfuscated and appears to be non-readable content, further suggesting a malicious payload rather than legitimate information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

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://aihr-iadh.org/uploads/FCK_files/file/21517453882.pdf
    • http://alhouti.com/userfiles/file/20650784915.pdf
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/992e9a8ee33d201f8228991748ebea5d/83425365842.pdf
    • http://www.bridalchapel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071f21083d1b---vajegoluwewitanitobap.pdf
    • http://adabaskimerkezi.com/upload/file/6300395998.pdf
    • http://bawaconstructions.com/editorData/file/96923814158.pdf
    • https://chamsocmuihong.com/wp-content/plugins/super-forms/uploads/php/files/71b4ft3v0qmi5qt3ugas4asfpm/36477013308.pdf
    • http://agro-vostok.ru/userfiles/file/7785663819.pdf
    • http://panziofabian.hu/fck_kepek/86256972223.pdf
    • https://robinio.de/wp-content/plugins/super-forms/uploads/php/files/g9pusfv47364qndi33qrfoietn/62092314642.pdf
    • https://equinox-e.com/upload/files/memujefatazubamakazeg.pdf
    • https://baileyelectrical.services/wp-content/plugins/super-forms/uploads/php/files/mf2bu0ioiiq3es38ms3d34u844/83162272509.pdf
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b2e481d7111---jaduk.pdf
    • https://soba05.org/wp-content/plugins/super-forms/uploads/php/files/989174c00defc1a53485c67f78f71b74/52678285073.pdf
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/25deb868f809c33e7cb770f4a56d2396/87957462079.pdf
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/10fbbbe25184bdab67153e59a4750f30/9497903837.pdf
    • https://tehnol.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b63d58f1437---13193947000.pdf
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/160dffbbd06275---14719007410.pdf
    • http://uniquehotelsolutions.com/files/others/89746691330.pdf
    • https://area5srl.it/file/1477582320.pdf
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c5803ea4fad---70787068941.pdf
    • http://tpdw.pl/userfiles/file/35598405926.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=immunotherapy+in+orthopaedics
    • 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_off0001350c.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1350C 16792 bytes
font_01_sfnt_off00014d1e.bin
d24771a6af516f1058453d67d8aec3f8b6a79d5536b0f91ca760f38ca131ee75
pdf-font-stream PDF embedded font (sfnt) at offset 0x14D1E 17536 bytes
font_02_sfnt_off00017afa.bin
69abb987b10e5bab17496585d7d4c3165ac1270ee63d1d207cb8eb3efa9fb908
pdf-font-stream PDF embedded font (sfnt) at offset 0x17AFA 10900 bytes