Malicious PDF — malware analysis report

Static analysis result for SHA-256 25b91f892e6a9484…

MALICIOUS

PDF

79.3 KB Created: 2021-05-27 22:18:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 228a292d4e5010496d2afcca5e3b35d7 SHA-1: 1492f062ce5d1f1e1ef1b110fc69afcc8aabdc9a SHA-256: 25b91f892e6a948432eeeaf930a54e18608e01d387762540286598e0611ed59a
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, indicating a link farm or SEO manipulation tactic. ClamAV and ML classifiers identified the file as malicious, specifically as a phishing trojan. The presence of numerous external URLs suggests the document's primary purpose is to redirect users to potentially harmful content or phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://xajibur.ru/123?utm_term=fractions+math+test+worksheets
    • https://bokosemebejira.weebly.com/uploads/1/3/0/8/130813317/powolizulakalotuluxe.pdf
    • https://wovusowi.weebly.com/uploads/1/3/4/8/134886666/guganadixiji-redivo.pdf
    • https://tixilumudesowor.weebly.com/uploads/1/3/6/0/136095614/5281017.pdf
    • https://cdn-cms.f-static.net/uploads/4413122/normal_6031c561890ff.pdf
    • https://gabubogoko.weebly.com/uploads/1/3/3/9/133997439/ed645170ba.pdf
    • https://mamunazeve.weebly.com/uploads/1/3/0/8/130814121/88e10a8.pdf
    • https://daruxugow.weebly.com/uploads/1/3/7/5/137511804/7337497.pdf
    • https://sonujeti.weebly.com/uploads/1/3/0/9/130969686/0a684b.pdf
    • https://cdn-cms.f-static.net/uploads/4486061/normal_60478e8b3d548.pdf
    • https://gavozosalaz.weebly.com/uploads/1/3/1/1/131163920/2476509.pdf
    • https://cdn-cms.f-static.net/uploads/4379720/normal_60511b81ce23f.pdf
    • https://satobolusiv.weebly.com/uploads/1/3/1/3/131398412/ganatekiwi.pdf
    • https://kolabobinojojiv.weebly.com/uploads/1/3/4/8/134880551/1362fea20ea0744.pdf
    • https://kofejadadamutu.weebly.com/uploads/1/3/4/3/134348877/jiwota-vakorewovutepi-senim-kinurasave.pdf
    • https://vebovaxuzukikom.weebly.com/uploads/1/3/4/3/134352383/5378508.pdf
    • https://busenijerebu.weebly.com/uploads/1/3/2/6/132695513/7266964.pdf
    • https://mabexerezigija.weebly.com/uploads/1/3/5/3/135324341/631348c7689fc48.pdf
    • https://pawuzoratifeze.weebly.com/uploads/1/3/4/4/134471058/pomim.pdf
    • https://nusuvonofa.weebly.com/uploads/1/3/1/8/131872273/1623813.pdf
    • https://jobeluraxofedir.weebly.com/uploads/1/3/4/3/134317239/57b552dd20.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://uploads.strikinglycdn.com/files/476115de-514d-4ecc-96a4-8a50a2d6eb3a/how_to_use_dslr_camera_nikon_d3400.pdf
    • https://uploads.strikinglycdn.com/files/48a04593-cb5e-4ca3-a085-01965525bf1d/binusizulufipujitusu.pdf
    • https://uploads.strikinglycdn.com/files/715d7cd6-860b-4746-a9eb-d97c58786f98/58194316408.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://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef1d.bin
7f24f233f673ef9592ad0cdac8eedf8d873fb7c9d650a542ea8e329541e8cbaa
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF1D 4908 bytes
font_01_sfnt_off0000ffa0.bin
0350fbea39fe7abc8409d23743ddeacf6b368a2ad6aa0cc7d00afa599af67d9a
pdf-font-stream PDF embedded font (sfnt) at offset 0xFFA0 10000 bytes
font_02_sfnt_off000121d6.bin
0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333
pdf-font-stream PDF embedded font (sfnt) at offset 0x121D6 4324 bytes